Latisse is marketed as a new use of an old medication to elongate and thicken eyelashes in those of us who have thin eyelashes.  The drug is an old glaucoma medication known as bimatoprost, which was observed to produce longer, thicker eyelashes during glaucoma treatment.  There can be a few side effects that are usually mild and supervision under a qualified physician is in order, but the results with continued use are typically very satisfactory in improving the cosmetic appearance of the eyes.