Mr Rowley was discharged after being admitted in June.
The news comes as an inquest is due to open for Dawn Sturgess, who died days after apparently coming into contact with Novichok.
A bottle was recovered from the home of Charlie Rowley, who is seriously ill in hospital.
Novichok victim Charles Rowley is "looking like a skeleton" in hospital, according to his brother who told ITV News he is getting better.
Officers initially believed Dawn Sturgess and Charlie Rowley had taken illegal drugs.
A man and a woman are critically ill in hospital after being exposed to Novichok.