JOHANNESBURG, April 10 (Reuters) - Nigeria's health regulator is recalling a batch of Johnson & Johnson children's cough syrup after finding an unacceptably high level of a potentially fatal toxic substance, it said on Wednesday.

Laboratory tests on Benylin Paediatric showed a high level of diethylene glycol, which has been linked to the deaths of dozens of children in Gambia, Uzbekistan and Cameroon since 2022 in one of the world's worst waves of poisoning from oral medication.

The syrup is used to treat cough and congestion-related symptoms, hay fever and other allergic reactions in children aged two to 12, Nigeria's National Agency for Food and Drug Administration and Control (NAFDAC) said in a notice on its website.

"Laboratory analysis conducted on the product showed that it contains an unacceptable high level of Diethylene glycol and was found to cause acute oral toxicity in laboratory animals," NAFDAC said.

Human consumption of the substance could cause symptoms like abdominal pain, vomiting, diarrhoea, headaches and acute kidney injury that may result in death, the regulator added.

J&J referred a request for comment to Kenvue, which now owns the Benylin brand after a spin-off last year. Kenvue did not immediately respond to a request for comment.

The batch being recalled was made in South Africa in May 2021 with an expiration date of April 2024. The regulator urged those with bottles from the batch to discontinue use or sale and submit them to its nearest office. (Reporting by Bhargav Acharya in Johannesburg and Bhanvi Satija in Bengaluru; Editing by Alexander Winning and Richard Chang)