Officers believe the two deaths and the serious illness of a third man could be linked to a bad batch of 'monkey dust' being sold in the Telford area.
It is not known whether any of the men had taken monkey dust, but police are concerned that their deaths and illness are connected to the drug.
The third man remains in a serious condition in hospital, West Mercia Police said, as they confirmed that the three incidents all happened separately.
Officers have now urged anyone who falls ill after taking the drug to seek medical help immediately.
Detective Inspector Lee Holehouse, from Telford CID, said: "Our inquiries are very much in the initial stages and it may be that these deaths are not connected but we want people to be aware there may be a bad batch of monkey dust circulating.
"If anyone has taken the drug and falls ill then they should seek medical attention immediately.
"The dangers of taking drugs are well known and all drugs pose a risk to those who take them but I would like to reiterate this additional danger."
One of the men found dead was in his late 30s and was found in a house in Madeley, the other was a man in his late 40s and found at a house in Merseyside. The man in hospital is in his 30s.
Symptoms include intoxication, blood shot eyes, hallucinations, suicidal thoughts, violence, slurred speech and smelling like prawns or vinegar.
Monkey dust is another name for MDPV, or methylenedioxypyrovalerone.
It is an addictive Class B drug usually sold in powder form or swallowed.
Its appearance is similar to cocaine – a white or brownish powder – although it is far cheaper.
Also known as dust or bath salts, the drug's effects are similar to ecstasy or mephedrone and last for up to five or six hours.
It is a stimulant which can cause feelings of euphoria and increased alertness but also lead to heart damage, depression and paranoia.
According to drugs information website Why Not Find Out, monkey dust can make people who take it smell of urine and it can also lead to skin rashes, insomnia, vomiting and headaches.
Anyone with information about the drug can contact police on 101 or Crimestoppers anonymously on 0800 555111.