A section of road in Salisbury was sealed off by police on Thursday evening after what officers called an "incident" involving a man in his 30s.
The street was closed at around 6.20pm and officers were spotted in protective white suits after a man was found near the Zizzi restaurant in Castle Street, which was visited by Sergei and Yulia Skripal before they were taken ill with Novichok poisoning.
But just three hours later, officers reopened the road and removed the cordon, saying the man had been assessed at the local hospital and there were "no concerns" for either his health or that of the wider public.
In a statement, Wiltshire Police admitted their response "may have looked alarming", but said the "highly precautionary measures" had been necessary.
In a statement, the force said:
It comes after another two people - Dawn Sturgess and Charlie Rowley - were also taken ill after coming into contact with the deadly nerve agent.
Ms Sturgess, aged 44, died on June 8, while Mr Rowley remained in the intensive care unit at Salisbury District Hospital, though he had regained consciousness.