Officers investigating the Novichok poisoning in Amesbury, which led to the death of Dawn Sturgess earlier this month, will be carrying out enquiries at the Boots store in the town centre.
Sturgess died on July 8 after she and her partner Charlie Rowley both fell ill at the end of June.
Rowley, 45, said the deadly nerve agent took just 15 minutes to poison Sturgess after she sprayed the “oily” substance on to her wrists believing it was perfume.
Rowley, who was discharged from hospital last week, has spoken about how he feels responsible for the death of his partner after he gave the mother-of-three the bottle as a present.
He told ITV: “I do have a memory of her spraying it on her wrists and rubbing them together.
“I guess that’s how she applied it and became ill. I guess how I got in contact with it is when I put the spray part to the bottle… I ended tipping some on my hands, but I washed it off under the tap.”
Sturgess, 44, died in hospital eight days later, prompting a murder investigation amid fears her death was linked to the Salisbury poisonings of former Russian spy Sergei Skripal and his daughter Yulia on March 4.
The Metropolitan Police’s Assistant Commissioner Neil Basu has previously said Rowley visited Boots on Stonehenge Walk at around midday on June 30, and returned to his house around half an hour later.
Wiltshire Police said officers, likely to be in protective clothing, would visit the shop on Thursday morning to collect CCTV as part of the inquiry. Protective equipment will be worn on a precautionary basis, the force added.
The cordon at the home of Sturgess was lifted earlier this week, with investigators saying no contamination risk had been identified at John Baker House, the supported-living accommodation in Salisbury.
Public Health England’s advice is that the wider risk to the public remains low.
Rowley and Sturgess were victims of the second nerve agent incident in four months following the case of Sergei Skripal and his daughter Yulia.
They were found unconscious on a park bench in Salisbury in March.
In the aftermath, Home Secretary Sajid Javid accused the Russian state of using Britain as a “dumping ground for poison”, and demanded the Kremlin provide an explanation for the two episodes.