It was 6-year-old Zachary Nadeau who first realized something was terribly wrong. He opened the car door to find his younger sisters eating his mother’s prescription medication.

“He just came and tell me, ‘Mom, my sisters are taking some pills in your purse. Hurry, hurry, hurry,’” says mother Monique Herault.

Kassidy, 4, and her sister Haley, 3, were able to get the bottle open with their teeth. They were rushed to hospital by ambulance and placed in critical care. They were released four days later.

“I couldn't eat, I didn't sleep, I thought my children was going to die,” says Herault.

Now the family wants answers regarding the safety of the child-resistant bottle under the brand name Secu-Rigo.

It is a common type of container that uses aligned arrows on the bottle and lid to open. When the arrows are separated the bottle should be locked.

 “That bottle was supposed to be child-proof. And my daughter of four years old opened it with her teeth,” Herault says.

The manufacturer of the bottles Richards Packaging released this statement:

We take these incidents very seriously all of our products meet the CSA standards governing child-resistant packages.

All of our products are tested by the CSA and their inspectors audit our manufacturing facilities on a regular basis.

Please be aware that all prescription containers are child-resistant not child-proof and that parents are the first and best guardians of their children’s safety when it comes to the proper storage and security of any medication.

“How can this be CSA approved if children almost died over it. The company is not manufacturing their product right,” says Derrick Nadeau, the children’s father.

The family says they notified their local pharmacist who tested out the other bottles. They say staff found the same problem and pulled the rest of the stock from the shelves.

Monique Herault says it’s a start, but she won’t find closure until the company recalls the bottles.

"I don't feel safe. I mean I watch every step they take. It's a nightmare."

With a report from CTV’s John Hua