Ellie, from Rochester, New York, said she can't stand the taste of her generic Xanax, "I don't place it on the center of my tongue and drink water quickly, I'll get this horrible, like bitter and sour taste that lingers," she wrote in an e-mail form to ABCNews.com. Ellie refrained from giving her last name.
Parents who have to deal with rank-smelling medications have twice the struggle.
"My son, Will, who is 11 years old, underwent a bone marrow transplant in June 2009 to treat his severe aplastic anemia. Now he is on an immunosuppressant medication, cyclosporine, that tastes and smells like skunk!," wrote Rebecca Crisler, of Albuquerque, N.M. Crisler said many kids in the bone marrow transplant unit struggle to take the medicine.
"He bravely takes it each day, but it is disgusting!" she wrote.
"Any medicine with an undesirable taste or smell is usually associated with poor compliance," said John Forbes, of the American Pharmacists Association. Forbes said poor compliance -- meaning patients don't take their medicine -- is very common for children taking oral solutions such as the antibiotic Augmentin.
"Fortunately, there are ways to circumvent this problem. Most pharmacies have the ability to flavor an oral solution to increase palatability and compliance," said Forbes.
Forbes also pointed out that not all metformin pills will have the fishy smell, and some generic brands are particularly more pungent than others. "This complaint is uncommon in patients who take brand name metformin, which may be manufactured with an outer coating that masks the poor smell," he said.
Bristol-Myers Squibb (BMS) sold metformin as Glucophage and Glucophage XR (extended release), before generic forms appeared.
"BMS is aware that the inherent characteristics of metformin have been associated with a mild odor upon opening of the bottle, so these type of reports are not unexpected. It's important to note there has been no correlation between an odor and the efficacy of metformin which has been on the market in the US since 1995," BMS spokesman Ken Dominski said in a statement to ABCnews.com. "Metformin continues to be the backbone of type 2 diabetes therapy in the US and has helped millions of people worldwide to manage their disease."
When asked about metformin's smell, the U.S. Food and Drug Administration pointed out that odor often has nothing to do with the quality of some drugs.
"The FDA is aware of reports regarding a strong odor associated with this product. However, these types of odor or taste complaints are not necessarily indicative of a drug quality or safety concern; often times, a bad odor or taste can occur as a result of the chemical composition of the drug product itself," FDA spokeswoman Shelly Burgess said in a statement to ABC News.
"The FDA evaluates drug quality complaints, including those concerning bad odor or taste, that are received through our drug quality reporting system to determine if a drug safety concern exists," she added.