Claims in this area run far ahead of what the science supports. It is common to read that hypnosis heals wounds, lowers inflammation, or fights off disease, and those statements should be set aside before anything useful can be said. There is no good evidence that hypnosis strengthens immunity in a way that prevents illness or treats a medical condition, and presenting it that way can lead someone to delay care they actually need.
What does hold up is a more modest and indirect story, and it runs through stress. Chronic, prolonged stress is associated with raised levels of hormones such as cortisol, and sustained high cortisol can dampen some aspects of immune function over time. This is the territory studied under the heading of psychoneuroimmunology, the field that examines how the mind, nervous system, and immune system interact.
Hypnosis enters only at the front of that chain, through relaxation. A focused, calm state may lower the stress-hormone load for some people, and in principle easing chronic stress removes one of the things that can weigh on immune function. That is a long way from saying hypnosis boosts the immune system. It is closer to saying it might reduce one form of pressure on it.
The research that exists is limited and mixed. Some small studies have reported changes in particular immune markers during or after hypnosis, but the findings have been inconsistent, hard to replicate, and difficult to separate from general relaxation or the ordinary ups and downs of stress. None of this establishes that hypnosis meaningfully changes how well a person resists infection, recovers from illness, or heals a wound.
The specific overclaims deserve a direct answer. Hypnosis does not heal wounds, does not reduce inflammation in any reliable, demonstrated way, and does not fight disease. Where those phrases appear, they are claims the evidence does not back. Anyone facing infection, an inflammatory condition, or a wound needs medical assessment and treatment, and a relaxation practice is no substitute for either.
Read carefully, the link between hypnosis and immunity is real only as a thin, indirect thread: less chronic stress may mean one less drag on a system the body runs on its own. The grander promises stretch that thread past what it can hold. The accurate position keeps relaxation as a possible help for stress and leaves immunity, infection, and healing to the body and to medical care.