Choose your toothpaste carefully – that's the latest from the Ministry of Public Health, which recently discovered three stores in San José selling tubes contaminated with a toxic substance.

On Friday, the ministry declared a national alert, urging citizens to denounce stores that continue to sell the contaminated toothpaste under the brand names Genial and Mr. Cool, both of which are made in China, according to the daily La Nación.

The toxic substance -- called dietilene glycol -- is also used as brake fluid for automobiles and has been blamed for a rash of deaths in Panama, where it was discovered mixed with medicines provided by that country's social security system.

According to La Nación, 300 units of the poison paste were sold in San José and the northwestern Guanacaste city of Liberia.

The National Center for Toxic Substances has not received any reports of affected people in Costa Rica, but Health Minister María Luisa Avila told the daily that people should beware of purchasing toothpastes with obscure brand names until the issue is fully resolved.

The ministry is in the process of closing commercial establishments that continue to sell these brands and is studying the possibility of filing complaints before the Prosecutor's Office against those who distributed the product in Costa Rica, the daily reported.

The substance in question, which has also been used as an industrial cleaning solvent, was responsible for poisoning 107 people in the United States in 1937, 85 people in Haiti in 1996 and, most recently, more than 100 people in Panama.

According to the U.S. Environmental Protection Agency (EPA), consuming even small quantities is often fatal and can lead to a breakdown of the central nervous system.

To report stores selling the toothpaste brands in question, citizens can call the Health Ministry at 221-6058, 222-1415 or 222-4800.

-Tico Times