Are you looking for a quick fix to lose weight but you don't want to go on a diet or sweat it out doing physical activity? This Sydney mum's near-death experience will make you think twice before opting for products that can promise you instant weight loss.

Elizabeth Katerina lost 25 kgs in eight weeks after taking slimming pills she bought online. However, she found herself barely recovering from a near-death experience, after discovering the pills almost took her life.

In a desperate bid to lose the weight she gained from pregnancy, the Sydney mum scoured all over social media to find a quick fix for her problem.

She then came across 3Action Sports Nutrition's Fatburner pills, which she purchased online from Belgium and took them as directed on the bottle.

After one week of taking the pills, the mum experienced light-headedness, dizziness, headaches, and an upset stomach.

Ms Katerina also told A Current Affair that on the tenth day of taking the pills, her heart rate reached 150 beats per minute which led her to call an ambulance. The doctors then told her that she had been "poisoned".

"The doctors at the Royal North Shore Hospital said to me 'please throw out those diet pills. Whatever is in those Fatburners, they're not good for you, they've overstimulated your system and you've been poisoned'," she said.

Now, Ms Katerina is taking several prescription drugs to get by. Aside from the medication, the mum is also seeing a cardiologist and gastroenterologist.

The mum told A Current Affair: "I would rather be curvy and healthy than consume what I consumed — what I thought was safe with online shopping."

"I wouldn't wish this upon anyone, not even my worst enemy."

3Action released a statement to A Current Affair saying that the company's Fatburner pills comply with Belgian and European legislation and are approved by the Belgian Food Safety Authorities.

3Action also said in their statement: "This product has been on the market since 2018 and we have never received a complaint or dissatisfaction about it before."

The mum left a negative review of the product on Facebook. She also claimed that the company told her that she needed to email them if she wanted to reach out instead of calling them on the phone.

The pills Ms Katerina used were not approved by the Therapeutic Goods Administration (TGA).

The TGA released a statement advising consumers to be cautious when purchasing medicines, dietary supplements and herbal preparations online.

"Products that are not regulated by the TGA may not meet Australian manufacturing quality standards, and could also contain undisclosed harmful ingredients or toxic contaminants that can pose a serious risk to health," the statement said.

3Action Sports Nutrition has now removed the option to ship the Fatburner pills to Australia from their website.