Medical marijuana legalization has a huge effect on the pharmaceutical industry, “Big Pharma”, because marijuana can and has replaced a number of pharmaceutical drugs. Especially now that marijuana support and legalization are growing, more patients are choosing marijuana over pharmaceutical drugs to treat their pain. Studies actually show that states with legalization laws have lower numbers of painkiller abuse and overdose. In these states, researchers found that prescriptions for painkillers and other classes of drugs decreased, making for a very interesting relationship between the marijuana and pharmaceutical industries.

Other research shows that legalization can take a multi-billion dollar bite from Big Pharma, especially  if all 50 states legalized marijuana, the pharmaceutical industry would lose an estimated $18.5 billion. In order to fight the growing marijuana industry, Big Pharma has supported groups opposing marijuana legalization. The pharmaceutical company Insys spent $500,000 to help block legalization in Arizona, which marks one of the largest ever single contributions to a marijuana opposition campaign. Big Pharma is unable to stop legalization though, so now a number of pharmaceutical companies are joining the cannabis market by producing their own marijuana products.