M SL 100 is Blue and round and identified as Sildenafil Citrate 100 mg. Mylan Pharmaceuticals Inc. supplies it. These pills are known to relax the muscles of the blood vessels, leading to increased blood flow in particular areas of the body. Many people buy M SL 100 pills for the treatment of Erectile dysfunction and belong to the drug classes agents for pulmonary hypertension, and impotence agents. Most importantly there is no risk in pregnancy.