Canadians taking natural health products containing the ingredient glucomannan should take it with a full glass of water or other fluid to avoid a choking risk, Health Canada advises.

Products containing glucomannan are approved in Canada to reduce appetite, manage weight and cholesterol levels, and treat constipation. The products come in tablet, capsule and powder form.

Health Canada said Friday that the need for the advisory came up during its work with manufacturers and distributors of products containing glucomannan, an insoluble fibre.

The products should be labelled to inform consumers:

• To take or mix the product with at least one cup of water or other fluid, because too little liquid may result in choking or blockage of the throat, esophagus or intestine.
• Not to take the products immediately before going to bed.
• Consult a health-care practitioner before use if pregnant, breastfeeding or have diabetes.
• Not to use the product if they have difficulty swallowing.

Anyone who experiences chest pain, vomiting or trouble swallowing or breathing after taking the products should seek immediate medical attention, Health Canada said.