Chloroquine and hydroxychloroquine are known for treating malaria but are actually no longer effective against malaria parasites due to the development of resistance. They are now used to treat autoimmune diseases. Recently, they are considered to treat viral infections, mores specifically COVID-19, due to their low toxicity, affordability, great tolerability, and their ability to regulate the immune system. Both are soluble in water with hydroxychloroquine being slightly more soluble than chloroquine. Chloroquine and hydroxychloroquine are known to have long half-lives of 38 days and 54 days, respectively. They can easily build up in tissue after prolonged exposure but are metabolized by the liver and excreted through urine. Some possible side effects include keropathy, maculopathy, and retinopathy.