NCCIH distinguishes between complementary (used together with conventional medicine) and alternative (used in place of conventional medicine) approaches. It notes that “researchers have done large, rigorous studies on a few dietary supplements, but the results often showed that the products didn’t work for the conditions studied.” It also states that “research findings suggest that several psychological and physical approaches, alone or in combination, are helpful for a variety of conditions,” giving examples such as acupuncture for some chronic pain, meditation for anxiety and depression symptoms, and yoga or tai chi for pain and quality of life. The page emphasizes that while there are indications some approaches may help, more needs to be learned about effects, safety, and interactions.

NCCIH advises that complementary health approaches should not replace conventional care that is known to be helpful. It states that “for most complementary health approaches, good scientific evidence of their safety and effectiveness is limited,” and emphasizes that some approaches “may not be safe” and that products can interact with conventional medicines. The page urges patients to discuss these approaches with their health care providers and to use them as a complement, not a substitute, especially for serious conditions.

NCI explains that “some CAM therapies have undergone careful evaluation and have been found to be generally safe and effective. These include acupuncture, yoga, and meditation to name a few.” At the same time, it notes that “less research has been done for most types of complementary medicine” and that “there are others that do not work, may be harmful, or could interact negatively with your medicines.” The page explicitly states, “It’s important to know that there are no studies that prove that any special diet, food, vitamin, mineral, dietary supplement, herb, or combination of these can slow cancer, cure it, or keep it from coming back,” and warns that some products can interfere with cancer treatment.

The review of 33 trials (8,270 participants) found that compared with usual care, "acupuncture did not appear to significantly clinically reduce pain, but seemed more effective in improving function immediately after treatment." It also states that compared with sham, "acupuncture may not be more effective in reducing pain immediately after treatment" and "perhaps did not appear to improve back-specific function immediately after treatment, or may not enhance quality of life in the short term." However, compared with no treatment, acupuncture "produced greater and clinically important pain relief" and improved back function in the immediate term. The authors conclude that trials with usual care as the control showed acupuncture "may not reduce pain clinically, but the therapy may improve function immediately after sessions" and that the certainty of evidence ranged from very low to moderate.

NCCIH notes that people with cancer often use complementary approaches for symptom management, but stresses that “there is no evidence that any complementary health approach can cure cancer or cause it to go into remission.” It summarizes research on specific methods and says that evidence for some (such as acupuncture for chemotherapy-related nausea and pain) is promising, while “for many other complementary health approaches, scientific evidence of safety and effectiveness is limited or nonexistent.” It explicitly cautions against using unproven products or practices as an alternative to conventional cancer treatment because this “may have serious health consequences.”

This Cochrane review states: "We are uncertain about the beneficial effects of manual acupuncture on pain intensity, pain relief and quality of life when compared to sham acupuncture or other therapies (such as mecobalamin, nimodipine, inositol, and Xiaoke bitong capsule)." One study comparing acupuncture with sham acupuncture found that the mean pain scores remained in the moderate range in both groups, and the authors conclude: "Overall, we do not have sufficient evidence to support or refute the use of acupuncture in treating neuropathic pain." They add that due to limited data, "there is insufficient evidence to support or refute the use of acupuncture for neuropathic pain in general, or for any specific neuropathic pain condition when compared with sham acupuncture or other active therapies."

BACKGROUND: "Homoeopathy seems scientifically implausible, but is popular and widely used. We aimed to assess whether the clinical effect reported in randomised controlled trials of homoeopathic remedies is equivalent to that reported in trials of allopathic (conventional) medicines for the same clinical conditions." RESULTS: "110 homoeopathy trials and 110 matched conventional-medicine trials were analysed. The median study size was 65 participants in homoeopathy trials, and 69 in conventional-medicine trials... CONCLUSION: 'When account was taken for these biases in the analysis, there was weak evidence for a specific effect of homoeopathic remedies, but strong evidence for specific effects of conventional interventions.'"

The article states that “the defining characteristic of alternative therapies is that their health claims do not meet evidence-based standards, and many, such as naturopathy, homeopathy, and energy healing, are scientifically implausible.” It reports that “rigorous trials supported by NIH and other noncommercial sources have failed to substantiate specific efficacy beyond a placebo effect for popular herbal supplements, chiropractic manipulation for back pain, or acupuncture for knee osteoarthritis or back pain.” It concludes that expenditure of approximately $2.2 billion by NCCAM/NCCIH from 1999–2017 for clinical trials “produced no sound, consistent evidence for the efficacy of any alternative therapies.” The article also cites data showing that “patients with four common cancers who chose alternative treatments as their sole initial therapy had a greater risk of death than matched controls who had conventional therapy.”

Several systematic reviews and meta-analyses have evaluated individual CAM modalities for CKD-related symptoms, but high-quality evidence directly comparing them with conventional therapies is limited. The authors note that while some herbal and acupuncture-based interventions show promise for symptom relief or quality of life, there is insufficient robust randomized controlled trial evidence to conclude that CAM is as effective as, or superior to, standard medical management for CKD progression or hard clinical outcomes.

OBJECTIVES: "To systematically review the evidence for the effectiveness of homeopathy in childhood and adolescence ailments." RESULTS: "Thirty-two randomized clinical trials were identified. The methodological quality was variable but generally low." CONCLUSIONS: "There is no evidence for the effectiveness of homeopathy for childhood and adolescence ailments."

NCCIH summarizes research on acupuncture, stating that for some pain conditions such as low-back pain, knee osteoarthritis, and neck pain, acupuncture "may help" and is recommended in some clinical guidelines as an option. However, it also notes that a 2016 review of 20 studies (1,639 participants) "indicated that acupuncture was not more effective in relieving cancer pain than conventional drug therapy." Overall, NCCIH characterizes acupuncture as having evidence of benefit for some types of pain but not clearly superior to conventional treatments and with limited or insufficient evidence for many other conditions.

This systematic review identified 56 economic evaluations of CAM, including 39 full evaluations, across a range of conditions and therapies such as acupuncture, manual therapy, spa therapy, guided imagery, relaxation therapy, and biofeedback.[1] The authors report that in a subset of higher-quality studies, some CAM therapies 'may be considered cost-effective compared to usual care' and in nine comparisons CAM was 'shown to be superior to usual care (better effects and lower costs, similar effects and lower costs, or better effects and similar costs).'[1] However, they also emphasize that reporting quality was often poor and that there remains 'a paucity of rigorous studies that could provide conclusive evidence of differences in costs and outcomes between other complementary therapies and orthodox medicine.'[1]

BACKGROUND: "Recent meta-analyses of randomized controlled trials in homeopathy have suggested that homeopathy is more than a placebo response." METHODS: This was "an international, multicenter, comparative cohort study" in primary care for acute respiratory and ear complaints. RESULTS: "Four hundred and fifty-six (456) patient visits were compared: 281 received homeopathy, 175 received conventional medicine. The response to treatment as measured by the primary outcomes criterion for patients receiving homeopathy was 82.6%, for conventional medicine it was 68%." Adverse events: "The adverse events for those treated with conventional medicine was 22.3% versus 7.8% for those treated with homeopathy." CONCLUSIONS: "Homeopathy appeared to be at least as effective as conventional medical care in the treatment of patients with the three conditions studied."

OBJECTIVE: "To compare the efficacy and safety of individualized homeopathic treatment (IHT), fluoxetine and placebo in peri- and postmenopausal women with moderate to severe depression." METHODS: Women were randomized to IHT, fluoxetine 20 mg/day, or placebo for 6 weeks. RESULTS: "After 6 weeks of treatment, there was a significant difference in favor of IHT and fluoxetine, compared with placebo, in the mean change in the Hamilton Rating Scale for Depression (HAM-D) total score"; IHT improved HAM-D by 5.0 points more than placebo and fluoxetine by 3.2 points. "There was no significant difference between IHT and fluoxetine" on the primary outcome.

OBJECTIVE: To compare individualized homeopathic treatment with conventional therapy in children with acute otitis media. METHODS: Pragmatic randomized controlled trial in India involving 81 children, allocated to homeopathy or conventional treatment (analgesics, antipyretics, anti-inflammatory drugs and antibiotics as needed). RESULTS: According to a summary cited widely, in the conventional group all 40 (100%) patients were cured; in the homeopathy group 38 (95%) patients were cured, with 2 (5%) patients lost to last follow-ups. By day 3, more children in the homeopathy group were cured than in the conventional group. Antibiotics were prescribed in 39 of 40 (97.5%) conventional patients; no antibiotics were required in the homeopathy group.

The paper states that “evidence-based CAM (EBCAM) therapies have shown remarkable success in treating diseases,” arguing for integrating modern CAM systems into health care. It discusses examples such as acupuncture, herbal medicine, and mind–body therapies, asserting that for some conditions these approaches can be effective and may reduce side effects or improve quality of life. However, it also notes challenges including variability in product quality, lack of standardization, and the need for more rigorous randomized controlled trials to firmly establish effectiveness compared with conventional treatments.

This systematic review of randomized controlled trials on chronic low back pain states: "Ten RCTs (2122 participants) were included comparing acupuncture versus [conventional treatment] and 4 RCTs (374 participants) were comparing acupuncture plus [conventional treatment] to [conventional treatment] alone." In comparisons of acupuncture with non-pharmacological or pharmacological treatments separately, "no differences were found for pain and disability." When acupuncture was compared with the combination of pharmacological and non-pharmacological treatments, pain and disability were reduced in favor of acupuncture. When acupuncture was added to conventional treatment, pain and disability were reduced compared with conventional treatment alone, but the authors conclude: "We are uncertain whether acupuncture is more effective and safer than [conventional treatment]. In the comparisons without estimates’ imprecision, acupuncture showed promising results."

This systematic review and meta-analysis evaluated randomized controlled trials of acupuncture versus sham acupuncture and conventional drugs (e.g. benzodiazepines) for chronic pain-related insomnia. The pooled results indicated that acupuncture was more effective than sham or medications in improving sleep quality and pain scores in the short term. However, the authors highlight that 'the overall quality of evidence was low to moderate' due to methodological limitations, small sample sizes, and risk of bias, and they caution that more rigorously designed head-to-head trials with conventional treatments are needed before firm conclusions can be drawn about relative effectiveness.

The review notes that "examination of the published work shows that while some trials do seem to indicate a specific mode of action for homeopathic remedies other trials do not and this is an issue that needs to be addressed at the trial design stage." It describes examples where benefit was not attributable to the remedy: "Homeopathy has clinical benefits in rheumatoid arthritis patients that are attributable to the consultation process but not the homeopathic remedy: a randomized controlled clinical trial." It also references a study of eczema where "both homeopathic and conventional treatment groups improved similarly over a 12-month period" in an observational cohort, with no placebo group.

This commentary discussing the 2005 Lancet meta-analysis states that after adjusting for study quality and small-study effects, "the effects seen in homoeopathy trials disappear, while those seen in conventional medicine trials remain." It concludes that the results "are compatible with the notion that the clinical effects of homoeopathy are placebo effects."

This large individual patient data meta-analysis of high-quality trials concludes that acupuncture is effective for chronic pain conditions but not dramatically superior to sham or conventional care. The authors report that for back and neck pain, osteoarthritis, and chronic headache, "acupuncture was superior to both sham and no-acupuncture controls" but that "differences between true and sham acupuncture were relatively modest." They state that effect sizes vs. sham were around 0.2, while effect sizes vs. no-acupuncture controls were around 0.5, indicating a small to moderate advantage of acupuncture over usual care but not a large superiority over controls designed to mimic the procedure.

This cohort study of patients with nonmetastatic breast, prostate, lung, or colorectal cancer found that those who used complementary medicine were more likely to refuse at least one conventional cancer treatment modality such as chemotherapy, surgery, or radiation. The authors report that “use of complementary medicine was associated with a higher risk of death” compared with nonusers, largely mediated by refusal of conventional treatment. They conclude that forgoing or delaying conventional cancer treatment in favor of complementary therapies can adversely affect survival.

This systematic review and meta-analysis examined randomized controlled trials comparing various CAM therapies (including acupuncture, chiropractic care, and herbal therapies) with standard medical care for different pain conditions. The authors report that 'CAM interventions showed small to moderate improvements in pain intensity compared with conventional care alone,' but that heterogeneity across conditions and interventions was high. They emphasize that while some modalities, particularly acupuncture, may achieve similar or slightly better pain reduction than pharmacological treatments in certain contexts, the evidence base is inconsistent and limited by trial quality and size.

This overview describes NCCIH as a U.S. government agency whose mission is to “determine, through rigorous scientific investigation, the fundamental science, usefulness, and safety of complementary and integrative health approaches and their roles in improving health and healthcare.” It notes that NCCIH applies scientific methods of experimentation and verification to CAM practices to assess their safety and efficacy. The article emphasizes that NCCIH plays a key role in “exploration and validation of CAM approaches,” providing evidence-based information and clinical trial data, but also highlights that the empirical research base for many CAM modalities has been limited or of low quality.

In this systematic review of acupuncture for non-specific low back pain, the authors found that acupuncture "showed statistically significant improvements in pain and disability compared with no treatment" but that when compared with other active treatments (such as nonsteroidal anti-inflammatory drugs, physical therapy, or usual care), the differences were small and often not clinically important. The review notes substantial heterogeneity and variable risk of bias and concludes that acupuncture may be considered as an adjunct or alternative in multimodal management rather than a clearly superior stand-alone therapy over conventional care.

This workshop report reviews methods and existing evidence on CAM effectiveness. It notes that systematic reviews and meta-analyses of CAM often find 'a paucity of studies of the highest methodological quality' and that positive findings for some interventions (such as acupuncture for certain pain conditions) coexist with many inconclusive or negative trials. The report emphasizes that the same rigorous standards used for conventional medicine should be applied to CAM and that, in most areas, 'evidence is insufficient to state that CAM therapies are as effective as conventional care across conditions,' though selected modalities may perform comparably in specific indications.

This National Academies chapter describes a framework in which 'the same principles of evidence and standards of treatment effectiveness should apply to all treatments, whether conventional or CAM.'[4] It notes that some CAM practices (e.g., osteopathic manipulation) have accumulated sufficient evidence to become integrated and 'fully accepted as an effective treatment modality' within mainstream medicine.[4] At the same time, it stresses that where medical evidence indicates 'either serious risk or inefficacy,' clinicians should avoid or discourage the therapy, and that for many CAM modalities, evidence regarding efficacy remains inconclusive, preventing broad claims of equivalence with conventional treatments.[4]

The NIH consensus statement on acupuncture for chronic pain acknowledges that "acupuncture appears to be effective for the treatment of certain pain conditions" but emphasizes that, in many studies, "acupuncture is comparable with, but not clearly superior to, conventional therapies" and that methodological issues complicate interpretation. It concludes that acupuncture can be a reasonable option in comprehensive pain management, especially when conventional treatments are ineffective or poorly tolerated, but does not claim that it generally works better than standard medical care.

The UK National Institute for Health and Care Excellence (NICE) guidance on low back pain and sciatica states that acupuncture should *not* be routinely offered for managing low back pain with or without sciatica. The recommendation section says: "Do not offer acupuncture for managing low back pain with or without sciatica." The guideline bases this on evidence that acupuncture showed at best small benefits over sham or usual care, which did not justify routine use compared with other non-invasive treatments.

This review article explains that 'as research has demonstrated, many complementary treatments — including acupuncture and various supplements — are safe and can be effective,' but it also states that 'there is no scientific or medical evidence to show that complementary treatments can help treat or cure conditions such as cancer.'[2] It notes that conventional treatments like chemotherapy and radiation have undergone 'rigorous scientific testing to demonstrate their safety and effectiveness,' whereas many complementary therapies are primarily used to alleviate side effects or improve quality of life rather than to replace standard care.[2]

This 2024 review summarizes WHO's position on traditional, complementary and integrative medicine. It notes that the WHO strategy encourages member states to evaluate traditional and complementary practices using 'rigorous research methods including randomized controlled trials and systematic reviews.'[7] The authors point out that while some traditional and complementary therapies have evidence for safety and effectiveness in specific indications, 'most practices have not yet been tested with the same rigor as conventional medicine,' and thus evidence is generally insufficient to claim equivalence or superiority to standard biomedical treatments across diseases.[7]

The NYU evidence-based practice guide notes that “some argue that evidence-based complementary and alternative medicine is a contradiction in terms” and that patients face “an information landscape that [is] plagued by limited empirical research that is often misleading or of low quality.” It emphasizes the need to locate and appraise high-quality research when considering CAM and points out that the quantity and quality of evidence supporting many CAM therapies remain much lower than for most conventional medical interventions.

Discussing randomized trials, the article notes: "By the year 2014, there were 104 good-quality randomized controlled trials (RCTs) on homeopathic remedies: 41% (43 trials) of these showed mainly positive outcomes, 5% (5 trials) showed mainly negative outcomes, and the remaining 54% (56 trials) were not conclusive." It adds that "the majority of these trials have resulted in inconclusive outcomes because of poor design or biased research methodology. Less robust trials are more likely to favor homeopathy over placebo." Citing the UK House of Commons Science and Technology Committee, it states: "there is no evidence suggesting homeopathy to be an effective treatment for any health condition."

This overview article defines alternative medicine as nontraditional healthcare practices such as acupuncture, chiropractic care, and herbal remedies, contrasted with traditional (conventional) medicine based on established scientific principles.[3] It states that alternative medicine is 'criticized for lacking rigorous scientific backing' while conventional medicine is considered effective but sometimes criticized for over-reliance on pharmaceuticals.[3] The article highlights the rise of integrative medicine, which seeks to combine evidence-based treatments from both systems, implicitly reflecting that only some CAM modalities have evidence comparable to conventional therapies in specific contexts rather than across the board.

Across multiple high-quality systematic reviews and guidelines, the overall pattern is that acupuncture tends to outperform no treatment or usual care for some chronic pain conditions but shows only small or no clinically important advantages over sham acupuncture or well-delivered conventional therapies such as analgesic drugs, physical therapy, or exercise programs. Major health bodies generally describe acupuncture as a possible adjunct or alternative for selected indications rather than as a treatment that consistently works as well as or better than the full range of conventional medical options.