A young man with anxiety ended up with serotonin poisoning after brewing a cup of lavender tea, a herbal remedy to calm nerves, Australian doctors report.

They say the case is a reminder to doctors to always ask patients about their complementary preparations in light of potential interactions with pharmaceutical drugs.

The 29-year-old had presented to a Melbourne ED with facial spasms, lower limb rigidity, ataxia and tremor that had developed over the previous 24 hours

Five days prior to attending hospital, he had begun taking 50mg of sertraline daily, prescribed by a psychiatrist for anxiety, according to a case report in Emergency Medicine Australasia.