An elderly man has suffered the first recorded case of anaphylaxis from Chlorella vulgaris, a supplement increasingly being used for a range of medical conditions, Melbourne doctors report.

The 75-year-old man’s problems started when he ingested powdered C. vulgaris, a microalga, which he normally fed to his pigeons to prepare them for racing, write doctors from the general medicine department at Northern Health.

On targeted questioning, he admitted he taken two 4g doses of the C.vulgaris supplement — the first the day before his hospitalisation and the second several hours prior.

The anaphylactic symptoms began three hours after the second dose.