As a general rule of thumb there are 20 drops per mL in liquids close to the density of water. The size of a drop depends on the fluid and the dropper as well, but 20 drops in an mL is generally the best estimate. Since your bottle is 5 mLs: 5mL x 20 drops/mL: 100 drops total. So there are about 100 drops in a 5mL bottle of Besivance. Votes: +1.