Immunomodulation by morphine and marijuana

The immunomodulatory effects of morphine and the active components of marijuana, particularly tetrahydrocannabinol, on various aspects of the host immune parameters include alterations in humoral, cell-mediated and innate immunity. Most studies have shown immunosuppressive effects due to use of these abused substances, although there are reports that they may not produce any deleterious effect and may even enhance some aspects of host immunity. They reduce resistance to cancer growth and microbial pathogens in animals.