- Research suggests that daily low dose aspirin doesn’t appear to reduce a person’s risk of colorectal cancer.
- Frequent aspirin use may increase a person’s risk of bleeding in and around the brain.
- Experts say you can lower your colorectal cancer risk with lifestyle habits such as eating a plant-based diet, limiting alcohol consumption, and exercising daily.
A daily regimen of low dose aspirin probably does not significantly reduce the risk of colorectal cancer but may increase the risk of bleeding in the brain area, according to a large-scale analysis of previous research.
Researchers reported that daily aspirin probably does not help in preventing colorectal cancer in the first 15 years of use, although it might have some preventive benefits in the longer term.
However, the researchers stated that they are “not confident” in the long-term assessment.
They also reported that daily aspirin use may increase deaths from colorectal cancer in the short term but may help reduce deaths after 15 years.
Again, the researchers noted they are “not confident” in these conclusions.
They did report that daily aspirin use may increase the risk of bleeding outside the skull as well as bleeding in and around the brain.
“It is not possible to draw definitive conclusions or outline specific implications for the routine use of aspirin for [colorectal cancer] primary prevention based on the current evidence,” the researchers wrote. “Our findings reveal complex, time‐dependent preventive effects and concerns about potential harms for clinicians and patients to consider.”
Ketan Thanki, MD, a colorectal surgeon who specializes in benign and malignant disease of the colon, rectum, and anus at the MemorialCare Todd Cancer Institute at Long Beach Medical Center in California, said this latest report provides cautionary advice for anyone considering an aspirin regimen.
“This study demonstrates limited (if any) protective benefit from aspirin on risk of developing colorectal cancer in the general population,” Thanki told Healthline. “With the known potential complications of long-term aspirin use, I would recommend that people don’t take daily aspirin solely with the intent of reducing your risk of developing colorectal cancer.”
To reach their findings, the researchers analyzed data from 10 randomized controlled clinical trials.
They compared aspirin and other nonsteroidal anti‐inflammatory drugs (NSAIDs) with either no treatment or a different treatment for preventing colorectal cancer or colorectal adenoma in the general population.
The studies included more than 120,000 participants. Most of the research was conducted in North America and Europe. Low‐dose aspirin (75-100 mg per day) was typically used, although three studies evaluated higher doses.
The researchers said they found that daily aspirin “probably results in little to no difference” in reducing colorectal cancer risks after 5 to 15 years of use. They added that aspirin might slightly reduce colorectal cancer risk after 15 years of use.
“I would advise that you only consider daily aspirin for this purpose, either if you have a genetic syndrome that predisposes you to cancer (specifically Lynch Syndrome) or have had adenomatous polyps removed during a prior colonoscopy,” Thanki said.
“In those populations, there is good evidence that it may decrease risk of cancer and may decrease risk of adenoma recurrence, respectively. Those patients should speak with their doctors.”
The researchers also reported that daily aspirin “may increase mortality” from colorectal cancer between 5 and 10 years of use, as well as producing “little to no difference in mortality” between 10 and 15 years, and a possible reduction in mortality after 15 years.
They added that aspirin “may result in little to no difference” in colorectal adenoma between 5 and 10 years, but “the evidence is very uncertain.”
The researchers also noted that daily aspirin use produced “little to no difference’ in overall serious adverse events, but they said “aspirin does increase the risk of serious extracranial hemorrhage” and “probably increases the risk of hemorrhagic stroke.”
The researchers said their findings should raise concerns for medical professionals and patients alike.
“The uncertain and delayed potential for benefit must be weighed against a definite harm,” they wrote.
“In light of the mixed evidence, clinical practice should continue to center on an individualized assessment and a shared decision‐making process, carefully balancing a patient’s established cardiovascular risk profile against their risk of bleeding,” the researchers wrote.
There has been conflicting research in recent years over the benefits and the risks of daily aspirin use as a cancer prevention tool.
The new research contradicts an August 2024 study that reported that regular aspirin use can lower the risk of colorectal cancer, especially in people who have obesity or have unhealthy lifestyle habits such as smoking.
An April 2024 study also concluded that daily aspirin may have some protective benefits against colorectal cancer, perhaps by enhancing the body’s ability to detect cancer cells.
However, a January 2026 study reported that daily aspirin did not appear to reduce cancer in older adults but stated it might increase the risk of cancer-related mortality in older population groups.
The contrast in research has prompted at least one government agency to revise its recommendations.
However, the task force
Experts concur that people should consult with their doctor about whether daily aspirin is beneficial for them.
“It may decrease the risk of… preeclampsia in high risk pregnancies, and, as we discussed, polyps and tumors in the colon. It is important to know that this is highly nuanced and you should always talk with your doctor to see if daily aspirin use is right for you,” he explained.
Katherine Van Loon, MD, a specialist in gastrointestinal cancers at the University of California San Francisco, said the January 2026 study indicates that a patient’s age can be a determining factor in whether daily aspirin use should be initiated.
“Age of aspirin initiation also seems to play a role and younger patients may benefit more,” she told Healthline in an earlier interview. “For now, I think we can say that we shouldn’t initiate aspirin therapy in an older adult for the sole purpose of cancer prevention.”
- eating more plant-based foods
- consuming less red meat and processed meat
- limiting alcohol consumption
- quitting smoking
- maintaining a healthy weight
- exercising daily
“A lifestyle of moderation is most important in reducing your risk of colorectal cancer,” he said. “Diet and exercise are the best and easiest ways you can decrease your cancer risk.”
“Daily exercise and weight reduction are also key. Try avoiding tobacco use,” he added. “Lastly, get your screening tests done. Colonoscopy is the best way to prevent and detect cancer, but other modalities like Cologuard are also now available.”
Van Loon shared a similar philosophy.
