SINGAPORE - Four men were arrested and illegal drugs worth about $40,000 were seized in a joint operation by the authorities in Geylang on Wednesday (Dec 23).

During the seven-hour operation by the Health Sciences Authority (HSA), Central Narcotics Bureau (CNB) and Singapore Police Force (SPF), four Singaporean men in their 20s were nabbed. They are currently assisting in investigations.

Cough syrup, prescription drugs and sexual enhancement drugs with an estimated street value of $40,000 were seized.

Health products from street peddlers and unknown sellers may be illegal, counterfeit or substandard, the agencies warned in a statement on Thursday.

They may contain undeclared, potent ingredients and toxic substances which can cause serious side effects when consumed.

Members of the public who encounter any illegal sale of cough syrup, sexual enhancement drugs and other health products can report them to HSA's enforcement branch by calling 6866-3485 during office hours or by e-mailing hsa_is@hsa.gov.sg.