Relatives of a woman and her son who died after receiving treatment with the drug Heparin made by Baxter International Inc. urged a congressional subcommittee Tuesday to protect patients from unsafe drugs.

Leroy Hubley, declared his wife and his son died after suffering reactions of the blood thinner Heparin when they were undergoing kidney dialysis at a medical clinic in Ohio. Among the side effects they observed were diarrhea, abdominal pain and trouble breathing.

The son's widow was also present before the U.S. lawmakers and said they never thought the lifesaving medication they were relying on could be contaminated.

I want to know what is going to be done to rectify the matter. I want to know if my daughter, Dawn, and the millions of others who continue to receive dialysis are safe, Hubley said according to Reuters.

The contaminated drug Heparin has been linked to 81 deaths in patients with similar reactions and the contaminant has been detected in heparin supplies in 13 countries according to the Food and Drug Administration.

Baxter recalled Heparin after it found it was contaminated in a Chinese plant that made the drug's active ingredient. Hubley and other relatives of heparin victims called for actions to keep medicines free of contamination.

Baxter's chairman and Executive President told the Congressional Committee that heparin appears to have been deliberately contaminated.

The Food and Drug administration has issued warning letters to the Chinese plant that made the drug's active ingredient.

However, Chinese researchers have concluded after making an investigation that the cause of deaths related to Heparin were not related to the contaminant found in the drug.

Jin Shaohong, deputy director general of the China National Institute for the Control of Pharmaceutical and Biological Products said the contaminant oversulfated chondroitin sulfate - that is not a natural part of heparin- could not have caused the reported reactions.

He said the cause of the reactions could be related to other contaminants, problems with the device used to inject the drug or health factors.

Shares of Baxter were 0.38 percent up at $62.87 on the New York stock Exchange.