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CNN  — 

The US Food and Drug Administration has issued a warning against buying or using certain eye drops from Dr. Berne’s and LightEyez due to microbial contamination.

The drops contain methylsulfonylmethane or MSM, a naturally occurring organosulfur compound popular in complementary and alternative medicine, as the active ingredient.

The FDA says Dr. Berne’s agreed to recall its MSM Drops 5% Solution after sampling and testing showed contamination with bacteria and fungus.

Samples of LightEyez MSM Eye Drops – Eye Repair were found to have four types of bacteria in them, the FDA says, but the company has not responded to the agency’s requests to discuss concerns or recall products.

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“These products are unapproved drugs and illegally marketed in the U.S.,” the FDA said in an announcement Tuesday. “There are no legally marketed ophthalmic drugs that contain MSM as an active ingredient.”

Consumers who have these products should discard them.

“Using contaminated eye drops could result in minor to serious vision-threatening infection which could possibly progress to a life-threatening infection,” the FDA announcement says.

No adverse events have been reported in connection with the products, but anyone who has signs of an eye infection should seek medical care immediately. Health care professionals and consumers can report adverse events or quality concerns with any medicine to the FDA’s MedWatch program.