A cancer patient on the drugmaker’s infection med really did see a “Wookiee,” you know, those tall, hairy aliens who appeared in ‘Star Wars.’ This one, however, wasn’t on a movie screen, but leaning over the bed. Another patient, however, had a more serene experience and encountered scenic images of New York, presumably not the subway at rush hour.

In fact, Bloomberg News reports that about 12 percent of Vfend patients hallucinations, according to research presented at a medical meeting today. The visions appeared within 24 hours of starting the drug, and were more common when Vfend was given intravenously than orally, the National Institutes of Health scientists reported.

Other hallucinations included “ugly and unfamiliar” faces; scenic images of Montana; unfamiliar and silent people entering the room, and “beautiful places” seen from the vantage point of a passenger on a train. For most patients, the apparitions stopped when they switched to either pills of Vfend, or a liquid dosage.

About 13 million patients have taken the drug to treat fungus infections, according to Pfizer. Many in the study described the illusions as “funny and innocuous,” researcher Dimitrios Zonios told Bloomberg a few days ago. But he says the side effect shouldn’t deter someone from taking the med.

“Doctors should underline the possibility of seeing or hearing strange things, to offer patients reassurance before they start seeing flying Christmas trees,” said Zonios, a NIH investigator, offering yet another patient’s hallucination. He presented the findings at the Interscience Conference on Antimicrobial Agents and Chemotherapy taking place this week in Chicago.

Vfend is used to treat serious fungal infections such as aspergillosis, which begins in the lungs and can spread to other organs by blood. Invasive fungal infections can be life-threatening to people with compromised immune systems, including cancer patients receiving chemotherapy, according to the NIH.

The current data didn’t address why patients might experience hallucinations. The authors wrote that “a possible relation to high blood levels” for the drug “is a subject of ongoing study.”

It’s important for docs to know that hallucinations are a side effect of Vfend, so they don’t mistakenly diagnose patients as psychotic, says John Bennett, head of the clinical mycology section of the National Institute of Allergy and Infectious Diseases. “These people aren’t going crazy,” he says. “They’re lucid and oriented.”

“Cases of treatment-emergent hallucinations have occurred in clinical studies and are described in the product labeling for Vfend,” says Pfizer spokeswoman Shreya Prudlo. “Health care professionals should be aware of the risk of this potential side-effect so they are able to manage this symptom and reassure patients.”