Five men were reportedly arrested over the alleged production of fake malaria drugs in Ikotun, Lagos.
The suspects were allegedly caught making unregistered medicines inside an abandoned building.
One of those arrested was identified as 47-year-old Emeka Madu.
Madu and four others were reportedly found at the location where the drugs were being produced.
The case has raised fresh concerns about the dangers of fake medicines in Nigeria.
Many Nigerians treat malaria regularly without knowing whether the drugs they buy are genuine.
“Month in, month out, you’ll keep treating malaria not knowing you’re taking a fake medication.”
The alleged operation also highlights the risks created when unregistered medicines reach unsuspecting patients.
Fake drugs can put lives at risk and may leave people without proper treatment. The incident has also sparked criticism over the enforcement of medicine regulations.
Some Nigerians have questioned the priorities of regulators when counterfeit medicines remain a serious concern.
The arrests reportedly followed efforts by authorities to uncover the illegal drug operation.

The suspects were allegedly producing the medicines for sale to members of the public.
The case serves as a reminder for Nigerians to check medicine packaging and buy from trusted sources.
Health authorities also encourage the public to report suspected counterfeit medicines.
For many families, access to safe and genuine medicine can make a major difference during illness.