Last year, retiree Puah Kim An bought a few bottles of Snake Powder Capsules, thinking that the drug could be the magic cure for his itchy skin problem as well as protect him from cancer.

"My wife heard about it from our neighbour's brother. He had taken five bottles of it and claimed that it's so good, it can cleanse the blood," the 58-year-old said in Mandarin. "He helped us buy it in Johor Baru."

Mr Puah's wife and daughter, both of whom did not wish to be named, also took some capsules.

Snake Powder Capsules purportedly contain natural ingredients, including a protein found in the venom of some snakes. The product is touted to treat illnesses such as pneumonia, hepatitis, skin problems, shingles, kidney disease, joint pain and rheumatism.

However, Mr Puah said the product did not relieve his itch. Instead, a few weeks after taking it, he was hospitalised with a drug- induced liver injury.

His daughter, who was taking slimming pills together with the capsules, also ended up with drug- induced liver injury. His wife did not suffer serious harm as she had not taken as many capsules as him.

"One day, my daughter had a fever and kept vomiting. She had to be hospitalised," said Mr Puah.

"We found out Snake Powder Capsules are banned here, so I stopped taking them. But a few days later, I also developed high fever."

RISK OF LIVER DAMAGE

Every year, more than 100 people report sick after taking alternative health products, according to a Singapore study published last year.

It said that from 2009 to 2014, the Health Sciences Authority (HSA) received 842 adverse-event reports - or an average of 140 cases a year - associated with the consumption of such products.

A total of 76 cases were associated with liver injury. Out of these cases, five people died.

Slightly over 60 per cent of the cases involved traditional Chinese medicine (TCM) products. Health supplements accounted for 28 per cent of the cases, while other traditional medicines like Malay jamu and ayurveda products accounted for the remaining 11 per cent.

"There are probably many more milder cases seen by doctors which did not warrant reporting," said Dr Loo Wai Mun, an associate consultant at the division of gastroenterology and hepatology at National University Hospital.

An HSA spokesman said the authority issued alerts last year for more than 10 harmful health products bought online or overseas.

He said: "Many of these products are touted as quick-fix solutions to enhance sexual performance, relieve pain or to treat weight loss and other chronic conditions.

"They are sold by street peddlers and online through blogs, forums and auction sites."

Dr Loo, who had attended to Mr Puah, said that if he had continued taking the capsules, he could have developed jaundice. Symptoms include the yellowing of the eyes and skin, and tea-coloured urine. In the worst-case scenario, he could also have suffered liver failure.

By the time patients who develop drug-induced liver injury seek help, they would have developed jaundice, abdominal discomfort or symptoms like fever or loss of appetite, she said.

In some cases, the liver injury is detected via a blood test as there may be no symptoms, she added.

Fortunately, Mr Puah and his daughter sought help early and have since recovered.

STEROIDS A DANGER INGREDIENT

In 2005, the HSA warned against taking Snake Powder Capsules as they have undeclared ingredients, including a potent steroid called dexamethasone. This can damage the liver by triggering viral hepatitis in a hepatitis B carrier or by causing fatty liver disease, said Dr Loo.

Snake Powder Capsules also contain antibiotics chloramphenicol and tetracycline; non-steroidal anti-inflammatory drugs such as ibuprofen; and chlorpheniramine, which is an antihistamine, she said.

Each of these Western drugs has different treatment indications, she said, and can be harmful when taken together in high doses.

Snake Powder Capsules also supposedly contain snake venom protein, which may harm the liver. These ingredients may interact with the patient's existing medications and result in liver toxicity.

The likelihood of side effects is increased as such products often contain multiple ingredients, said Dr Loo.

Steroids are also commonly found in adulterated products.

In October last year, the HSA warned against the consumption of LifeSparks 100% Natural Pain Relief Supplement as it contains dexamethasone.

This steroid was also found in Bee Brand Qi Li Xiang, which an unsuspecting user took to treat his body aches. When he stopped taking the product, he ended up with low blood pressure and low levels of cortisol, a key hormone that regulates metabolism.

Dr Loo said that taking products adulterated with steroids can lead to Cushing's syndrome, where one may develop high blood pressure, diabetes, muscle weakness and osteoporosis, as well as the risk of infections and easy bruising.

MYTH OF WEIGHT-LOSS PRODUCTS

Consumers should also be wary of products touting instant weight loss, which often claim to contain only natural ingredients such as fruit and herbal extracts.

But the truth is, they are tainted with banned or prohibited medications and substances.

The most common undeclared substance in weight-loss products is sibutramine, which was banned in many countries in 2010 due to serious safety concerns.

Dr Tham Kwang Wei, a senior consultant at the department of endocrinology and director of the Life Centre at Singapore General Hospital, said the banned ingredient suppresses one's appetite.

"The undeclared medication is often present in very high amounts, which can produce dramatic weight-loss effects," she said.

"But it can also cause serious adverse effects and toxicity." Such effects include a quickened heart rate, irregular heart rhythms, higher blood pressure, stroke and heart attack. One may also have mood swings, hallucinations and fits. And some people may even die from it.

Another prohibited ingredient in some adulterated weight-loss products is phenolphthalein, an obsolete compound that was used as a laxative in the past.

Dr Tham said: "Phenolphthalein can be associated with abdominal cramps and kidney disease. It has been reported to be associated with cancer in animal studies."

Even herbal medication can cause harm if used wrongly.

Ms Lim Lay Beng, a TCM practitioner at YS Healthcare TCM Clinic, said: "Prescriptions are usually made up of various types of herbs that not only boost the efficacy of the treatment, but also minimise the side effects of certain herbs."

She warned against self-medication with herbs and advised people to avoid buying any drugs or TCM medication online or from unauthorised dealers overseas.

Those keen on taking TCM supplements should inform their doctor about it, as these products may interact negatively with Western medication, said Dr Loo.

Dr Tham advised consumers to be wary of products that promise dramatic weight loss in a short time. Examples include losing more than 10kg in 21 days or "guaranteed results" from taking the pill alone, without having to change their diet or do any exercises.

There is little scientific evidence that dietary supplements are effective in weight loss, she added.