Health Canada is warning parents about two brands of medicinal childrens syrup after learning they contain an unapproved drug.

The federal department released a public advisory on Thursday warning about the use of Robikids and Solmux, both of which were advertised on Facebook by Kamshoppe.

Health Canada says the two brands contain a prescription drug called carbocisteine, which may pose serious health risks.

Side effects may include nausea, diarrhea, allergic reactions such as anaphylaxis, and gastrointestinal bleeding.

Do not use these products. Return them to your local pharmacy for proper disposal. Consult a health-care professional if you or your child have used either of these products and have health concerns, the Health Canada advisory says.

Prescription drugs can only be legally sold with a prescription. Buy your prescription drugs from licensed pharmacies only.

Health Canada says other countries use carbocisteine to treat conditions where too much mucus builds in the respiratory tract.

Along with its various side effects, the department says carbocisteine is also not recommended for anyone who is pregnant.

Health Canada says it will inform the public if it learns of other distributors or retailers that have offered the two products.

Consumers can confirm whether a health product is allowed to be sold in Canada by checking its eight-digit Drug Identification Number, Natural Product Number or Homeopathic Drug Number.

Other sources include the Drug Product Database and Licensed Natural Health Products Database.

Consumers can also report side effects or complaints to Health Canada.

Selling unauthorized health products in Canada is illegal. Unauthorized health products have not been approved by Health Canada, which means that they have not been assessed for safety, efficacy and quality and may pose a range of serious health risks, the department says.