Hallucinations are the perception of something that doesn’t exist. They can be auditory (heard), visual (seen), tactile (felt) or olfactory (smelled).

These hallucinations can have many causes. The most common causes are recreational drugs and dementia or delirium. But they can also be caused by high fevers or certain illnesses. Some people who have survived serious, life-threatening illnesses, like septic shock, report having very vivid hallucinations while they were in the intensive care unit (ICU).

Hallucinations are often very disturbing and the memories can last, but scientists don’t understand them. A few researchers are looking at how often hallucinations occur among critically ill patients. One study looked at 289 critically ill patients who had been in an ICU for 24 hours or longer and been sedated and intubated (placed on a ventilator). The researchers found that 9.3% of the patient had nightmares and 6.6% said that they had experienced hallucinations. For some people, the hallucinations continue, even after they are no longer in the ICU environment. Another study found that after leaving the critical care area, some patients experienced, “amnesia, continued hallucinations or flashbacks, anxiety, depression, and dreams and nightmares.”

No clear cause for hallucinations

There are theories as to why patients may experience hallucinations, but there are no clear explanations yet. Patients in an ICU are not only fighting a very serious illness, they don’t get a lot of rest. Nursing care is necessary and frequent, and lights are on in the hallways. Even with dimmed lights, patients might not be able to sleep. There is a lot of noise that comes from nurses moving about and talking, machines operating, and alarms beeping. The constant stimulation often causes sleep deprivation. Serious lack of sleep can cause psychological distress.

If you experienced hallucinations while hospitalized for sepsis or septic shock, you are not alone. Some of the people who have shared their stories in our Faces of Sepsis section mention that they saw or heard things that they knew weren’t there.

Getting help

If you are having a hard time dealing with the after effects of sepsis, which can include bad dreams, hallucinations, even memories of the hallucinations, this could be part of post-traumatic stress disorder, or PTSD. There are counselors and therapists who specialize in treating PTSD. They may use a variety of methods, including cognitive therapy, tapping techniques, or eye movement desensitization reprocessing (EMDR). Counseling can be an important component of full recovery from sepsis.


Hallucinations are also a change in mental status. This could be a sign of sepsis.

If you suspect sepsis, call 9-1-1 or go to a hospital and tell your medical professional, “I AM CONCERNED ABOUT SEPSIS.” 

what is sepsis

Would you like to share your story about sepsis or read about others who have had sepsis? Please visit Faces of Sepsis, where you will find hundreds of stories from survivors and tributes to those who died from sepsis.


Updated November 1, 2021.

Read Personal Stories of Sepsis and Hallucinations

Mickey Totten


I went to the hospital Sept 3rd 2019 with some chest and shoulder pain. I remember them wanting to do a test for meningitis. That’s the last thing I remember! As I later found out I had walking pneumonia. (Sepsis and Pneumonia) I was intubated but aspirated “food in my lung” and they think that’s where the sepsis started but I still don’t really know. At least that’s what I was told. I woke up in the ICU 17 days later with my leg swollen and red, as well as my hand, twice the normal size from 6 blown IVs ... Read Full Story

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Lore A.

Survivor, Survivor

After receiving some shocking news, my body collapsed due to a really bad case of anemia. Two blood transfusions led to lung failure and pneumonia and pneumonia then led to sepsis. (Sepsis and Pneumonia) I still remember feeling the worst pain and saying my partner’s name over and over again and “please don’t let me die. I just turned 34 please not yet, not like this.” The experience has been one of the hardest things I have ever gone through and I know not a day will go by that I won’t think of it in some way. One day ... Read Full Story

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Tammy H.

Survivor, Survivor, Survivor

I don’t know where to start. I had been stuck having breathing issues for over a month. I had been to the ER, Urgent Care. They both did X-rays, and COVID testing and sent me home saying it was just my asthma. So the day comes. I’m at the laundry mat doing laundry. I’m gasping for breath. The worker asked if I was OK. I said I was fine just needed to get home. I got home used my inhaler, did a breathing treatment, and realized it was only getting worse. I called my son into the room and told ... Read Full Story

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Poppy F.

Survivor, Survivor, Survivor, Survivor

My name is Poppy, and I want to tell you my full story to make sure you know the signs of sepsis- it almost took my life. I was 36 weeks pregnant. My breathing had been shallow for a week and it hurt to move; to describe the pain, it felt like I had been kicked in the ribs, like an awful stitch or heartburn every time I moved. It was becoming hard even just to sit up in bed in the morning because every moment sent ripples of pain through my body. (Sepsis and Pregnancy & Childbirth) I knew ... Read Full Story

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Rachael D.

Survivor, Survivor, Survivor, Survivor, Survivor

I had contracted bacterial pneumonia and was prescribed antibiotics. (Sepsis and Pneumonia) I started to take the antibiotics as soon as I got home from the doctor’s. The day after I still wasn’t feeling well, I was living alone at the time and didn’t want to be at home by myself so I went into work. That morning I was drinking a lot and not urinating. My fever then kicked in and I passed out at my desk around lunch time. By the time the ambulance arrived my skin was purple and they could barely get a blood pressure reading. All I remember ... Read Full Story

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Hallucinations are the perception of something that doesn’t exist. They can be auditory (heard), visual (seen), tactile (felt) or olfactory (smelled).