Complementary medicine refers to health practices used alongside conventional medical treatment, not in place of it. Think acupuncture during cancer care, yoga for chronic back pain, or massage therapy after surgery. The use of these approaches has nearly doubled in the U.S. over two decades, rising from 19.2% of the population in 2002 to 36.7% in 2022. That growth reflects both increasing scientific interest and a shift in how major medical centers think about patient care.
Complementary vs. Alternative vs. Integrative
These three terms get used interchangeably, but they mean different things. The distinction comes down to how a non-mainstream therapy relates to standard medical care.
- Complementary means a therapy is used together with conventional treatment. A patient undergoing chemotherapy who also receives acupuncture for nausea is using complementary medicine.
- Alternative means a therapy is used instead of conventional treatment. Choosing an herbal regimen in place of a prescribed medication is alternative medicine.
- Integrative health goes a step further. It coordinates conventional and complementary approaches into a single care plan, often involving multiple providers who communicate with each other. The emphasis is on treating the whole person rather than targeting one organ system or symptom in isolation.
In practice, truly alternative use is uncommon. Most people combine non-mainstream therapies with their regular medical care, which is why “complementary” is the more accurate term for what the majority of users are actually doing.
The Most Common Approaches
National survey data from the CDC paints a clear picture of what Americans actually use. Dietary supplements (not counting standard vitamins and minerals) top the list at 17.9% of adults. These include herbal products, fish oil, probiotics, and similar natural products. Chiropractic or osteopathic manipulation comes next at 8.5%, followed closely by yoga at 8.4% and massage therapy at 6.8%. Meditation (4.1%) and special diets (3.0%) round out the most popular options.
Americans spend heavily on these therapies. A national analysis found $30.2 billion in annual out-of-pocket spending on complementary approaches, with $12.8 billion going to natural product supplements alone. That supplement spending equals roughly a quarter of what Americans pay out of pocket for prescription drugs.
What the Evidence Shows
The strength of evidence varies widely depending on the therapy and the condition being treated. Some approaches have solid clinical trial data behind them, while others rest mainly on tradition or preliminary findings.
Yoga for chronic low back pain is one of the better-studied examples. A meta-analysis pooling eight randomized controlled trials with 743 patients found that yoga produced medium-to-large improvements in both pain and physical function compared to control groups. Those benefits shrank somewhat at follow-up but remained statistically significant, suggesting that ongoing practice matters for maintaining results.
Acupuncture has attracted substantial research interest, particularly for its effects on the body’s involuntary nervous system. The strongest line of investigation centers on its anti-inflammatory properties, with research exploring how needle stimulation activates nerve pathways that reduce inflammation. Clinical evidence supports its use for chemotherapy-related nausea and certain types of pain, though the mechanisms behind its broader effects are still being worked out.
Mind-body practices like meditation and guided imagery have shown benefits for mood, sleep, anxiety, and stress reduction in people with serious illnesses. Music therapy can reduce pain and anxiety in as little as 30 minutes. Massage has demonstrated measurable effects on psychological distress, nausea, pain, and fatigue. None of these are cure-alls, but as additions to standard care, they can meaningfully improve quality of life.
How Hospitals Use Complementary Therapies
Major medical centers have increasingly brought complementary therapies inside their walls, particularly in cancer care. Mayo Clinic’s integrative oncology program, for example, combines conventional treatment with acupuncture, massage, aromatherapy, music therapy, and mind-body practices like meditation and progressive muscle relaxation. These aren’t offered as replacements for chemotherapy or surgery. They target the side effects that standard treatment often struggles to fully control: fatigue, nausea, anxiety, pain, and sleep disruption.
This hospital-based model represents the integrative approach in action. Complementary therapies are selected based on evidence, coordinated with the patient’s oncology team, and tailored to specific symptoms. It’s a far cry from the image of complementary medicine as something that exists outside the medical system.
Safety Risks Worth Knowing
The word “natural” doesn’t mean risk-free, and the most important safety concern with complementary medicine is the potential for interactions with conventional treatments. St. John’s Wort, a popular herbal supplement for mild depression, is a prime example. It works by raising levels of serotonin, dopamine, and norepinephrine in the brain, which sounds helpful on its own. But if you’re also taking an antidepressant that raises serotonin (like sertraline or paroxetine), the combination can push serotonin to dangerously high levels, a condition called serotonin syndrome that can be life-threatening.
St. John’s Wort also speeds up how the liver breaks down other drugs, which can reduce the effectiveness of oral contraceptives, cancer medications, and HIV treatments. This is not a rare interaction or a theoretical concern. It’s well-documented in case reports and pharmacological studies.
Herbal supplements in general face lighter regulatory oversight than prescription medications. In the U.S., supplements don’t require pre-market approval for safety or effectiveness, which means quality and potency can vary between brands. Licensing requirements for complementary practitioners also differ significantly by state and by discipline. Chiropractors are licensed in all 50 states, but regulation of acupuncturists, naturopaths, and herbalists is less uniform.
Making Complementary Therapies Work Safely
The single most practical thing you can do is tell every provider what you’re using. That includes supplements, herbs, and any complementary therapies you receive. Many drug-herb interactions are predictable and avoidable, but only if your medical team knows the full picture. This is especially true before surgery, since some supplements affect bleeding, blood pressure, or anesthesia.
Look for practitioners with recognized credentials in their field. For acupuncture, chiropractic care, and massage, state licensing boards set minimum training standards. For approaches with less formal regulation, ask about training, certification, and experience with your specific condition.
Be cautious about any practitioner who suggests replacing your conventional treatment entirely, particularly for serious conditions like cancer, heart disease, or diabetes. The strongest evidence for complementary therapies is as an addition to standard care, not a substitute for it. The therapies that have earned a place in major hospital systems got there precisely because they were studied and applied as complements, used to fill the gaps where conventional medicine alone falls short.