Medics at the Beatson West of Scotland Cancer Centre in Glasgow made the appeal after the patients tested positive for respiratory syncytial virus.
One patient who had the virus, and had already been giving cause for concern, has died, according to NHS Greater Glasgow and Clyde (NHSGGC).
Four of the patients have already been discharged and sent home. Ten patients remain across the two wards but none are said to be giving any cause for concern as a result of the virus.
In-patients at the Beatson are “particularly susceptible to viruses”, prompting the NHS to ask that any visitors who have experienced cold or flu-like symptoms not to visit friends and family until at least 48 hours after the end of symptoms.
Visitors who do not have symptoms of the cold or flu are asked to observe temporary visiting times of 2pm-4pm and 6pm-8pm.
Dr Teresa Inkster, consultant microbiologist and infection control doctor at NHSGGC, said: “If you have any cold or flu-like symptoms, please do not visit loved ones in the Beatson until at least 48 hours after the symptoms have cleared up.”