Bromelain is an enzyme from pineapples used for it's anti-inflammatory actions. It is used in osteoarthritis formulas to help reduce swelling and pain. Here is the NIH Government sheet on bromelain merits. But a real revelation might be learned from this past story of use for bromelain. In the early 1960's, Doctors injected bromelain into the backs of patients with severe back pain which gave them general relief.
Then, quite suddenly, and much to the amazement of these Doctors and their patients, the FDA issued a cease and desist order for Doctors to immediately stop giving injections of bromelain. Obviously, the FDA must have had a valid reason for this action. From that point on, the only way to get bromelain was as a food supplement. In this form, it was obviously not as effective at reducing backbone swelling and pain. Some what later, about 40 years, here is a reference showing method of bromelain for reducing inflammation in scientific studies. Bromelain has continued to be a consistent preferred supplement for anti-inflammatory conditions. Now this new possible use being investigated for bromelain is against the inflammatory and anticoagulatory effects of COVID-19. ref