A cordon at an address in Tenzing Gardens, Basingstoke, has now been lifted.
This came about after a 37-year-old man attended North Hampshire Hospital in Basingstoke on Saturday 12 May.
He complained of feeling unwell having intentionally ingested something and currently remains in hospital.
Due to concerns raised about what the man had ingested, officers executed a warrant at an address in Tenzing Gardens, Basingstoke, on Sunday 13 May.
As a precaution, other emergency services attended the scene and those entering the address wore protective clothing.
Items were seized at the scene and sent for testing. Entry to the address was restricted while that testing took place, but there was no risk to the wider public.
Following consultation with Public Health England, the cordon at the address has been lifted with no risk to anyone attending the address.
We would like to thank residents for their patience while we dealt with this incident.
Enquiries are still underway to determine what, if any, criminal offences took place.
If you have any information relating to this case, please call 101 or contact Crimestoppers anonymously.