I am 5' 3" & 91.5 lbs. i want to gain weight badly and eat healthy but no weight is gained? i'd like like to like to try a medication. are there any?

Get thyroid checked: Sometimes the inability to gain weight is due to an overactive thyroid. This can be seen by doing a simple blood test. There are some medications to help increase appetite; however, first, i would work on slowly increasing portion sizes so that your tummy can tolerate more food before you feel "full". Also, add a "weight gain" protein shake/smoothy 1-2 times daily for extra healthy calories.

Depends on the cause: Several things can make it hard to gain weight. The main ones are inadequate intake of calories, need for hydrochloric acid ;/or digestive enzymes, malabsorption, inflammation of the intestines (possibly from intestinal parasites), celiac disease ; other food allergies, vitamin/mineral/amino acid deficiencies ; hyperthyroidism. Meds that address the cause should help.See a good doc for evaluation.