Cumbrian Police confirmed that two 31-year-old males remain in CIC at Cumberland Infirmary and three others, aged 36, 21 and 19, have since been discharged.
It is suspected that the five men took a non-pharmaceutical Blue Valium tablet and as a result suffered respiratory problems.
A 36-year-old woman from Carlisle has been arrested on suspicion of the supply of controlled drugs in connection with these incidents. She is currently being questioned by police.
Temporary Detective Inspector Colin Ritchie said: “We are continuing to remind people of the risks involved in taking any illegal substances or so-called legal highs – these can be life threatening.
“It is believed that all five of these men admitted to hospital have taken a drug called blue Valium.
“If you are offered this drug or have it in your possession please do not consume as it is very dangerous. You can take these to a chemist or hand them to a police officer if you come across them.
“Anyone who has taken such a drug or is feeling unwell is urged to seek medical assistance.”
Anyone with information on the supply of drugs is asked to contact police on 101 or Crimestoppers anonymously on 0800 555 111.
