If the medicine has a good taste, such as flavored chewable pills,1 recite the shehakol blessing.2 Flavorless medicine, such as pills that you swallow, do not require a blessing—but we do say a prayer that the medicine should be efficacious:

יהי רצון שיהיה לרפואה

"May it be Your will that this medicine shall bring healing."3

No blessing is recited on water that you drink to swallow down the pill. If you are swallowing it down with a beverage other than water, then you do recite the appropriate blessing on that beverage. (Tip: recite the blessing, take a sip, swallow the pill and then drink it down with the rest of the beverage.)

Rabbi Eliezer Posner