About 30% to 60% of chiropractic patients experience some kind of adverse effect after a session, but the vast majority of these are mild and short-lived, like temporary soreness or stiffness. Serious injuries, including stroke or significant nerve damage, are extremely rare, occurring in roughly 1 in 20,000 to 1 in several million treatments depending on the complication.
How Common Minor Side Effects Are
A systematic review of spinal manipulation studies found that 61% of all patients reported at least one adverse effect. The most common were headache (20% of patients), stiffness (20%), local discomfort (15%), radiating discomfort (12%), and fatigue (12%). A separate UCLA study of 280 patients put the number lower, at about 30%, with increased neck pain or stiffness being the most frequent complaint at 25%.
The difference between these figures likely comes down to how broadly “adverse effect” is defined and how patients are asked about it. Either way, the pattern is consistent: most side effects are mild muscle soreness, tiredness, or temporary stiffness. About 80% of these reactions begin within 24 hours of treatment and resolve on their own within a day or two. They’re comparable to the soreness you might feel after a vigorous massage or a new workout.
How Often Serious Injuries Happen
The serious complication that gets the most attention is vertebral artery dissection, a tear in an artery running through the neck that can lead to stroke. One widely cited estimate puts the risk at about 1 in 20,000 spinal manipulations, though researchers note the exact incidence is difficult to pin down because some cases go unreported and others may be coincidental rather than caused by the manipulation. People who develop arterial tears often had symptoms like neck pain or headache beforehand, which is also what brought them to the chiropractor in the first place, making cause and effect hard to untangle.
For lower back complications, the numbers are even more reassuring. A systematic review calculated that the risk of spinal manipulation causing a worsened disc herniation or a serious nerve compression syndrome called cauda equina syndrome is less than 1 in 3.7 million treatments.
A 2024 systematic review of spinal manipulation for acute neck pain found no serious adverse events across the included studies. In one trial, a single patient reported an unusual arm sensation after manipulation that resolved on its own without any neurological problems. In most of the other studies, no adverse effects were reported at all during treatment or follow-up periods lasting up to six months.
How This Compares to Other Treatments
For context, a risk assessment comparing cervical manipulation to NSAIDs (common over-the-counter painkillers like ibuprofen and naproxen) for neck pain found that NSAIDs carry a significantly greater risk of serious complications and death. The analysis concluded that cervical manipulation is safer by a factor of several hundred times. NSAIDs cause thousands of gastrointestinal bleeds and hospitalizations each year, a risk that compounds with regular use. Chiropractic side effects, while more immediately noticeable as soreness, rarely require medical intervention.
Children and Chiropractic Safety
A feasibility study of preschool-aged children found that 30% experienced at least one adverse event after chiropractic treatment. The most common were irritability or crying (11 out of 73 children) and fatigue or tiredness (11 children). Most reactions appeared immediately after treatment. Systematic reviews of pediatric chiropractic care confirm that adverse events in children are mostly mild and self-limiting.
Serious pediatric injuries are extremely rare but have been documented. In one case report, a 4-month-old developed quadriplegia after manual therapy, though the infant had an undiagnosed spinal cord tumor that wasn’t detected beforehand. Cases like these highlight why proper screening matters, especially in very young patients who can’t describe their symptoms.
When the Risk Goes Up
A review of 134 case reports of serious chiropractic complications found that many were preventable. Half the cases classified as preventable involved a preexisting condition in the patient’s spine that should have been caught during screening. Of those, 70% had active bone-related conditions like severe arthritis, osteoporosis, rheumatoid arthritis, or ankylosing spondylitis. Another 13% had vascular problems like atherosclerosis in the neck arteries.
There is a well-established list of conditions that rule out neck manipulation entirely. These include acute fractures, dislocations, osteoporosis, tumors, vascular disease, rheumatoid arthritis, spinal instability, infection, and use of blood-thinning medications. Red flags that should stop a session include dizziness, visual disturbances, facial numbness, ringing in the ears, difficulty speaking or swallowing, and any symptom that gets worse with neck movement.
Symptoms that don’t improve or that worsen after multiple manipulations are also a red flag. A competent chiropractor should be reassessing your response to treatment at each visit and changing course if things aren’t getting better. The cases where serious harm occurs most often involve either a missed preexisting condition or continued aggressive treatment despite warning signs.
What This Means in Practice
If you’re considering chiropractic care, the overall picture is that you have a roughly 1 in 3 chance of experiencing temporary soreness, stiffness, or fatigue afterward. These effects are normal and resolve quickly. Your risk of a serious complication is extremely low, particularly if you don’t have underlying bone, joint, or vascular conditions.
The most important thing you can do to reduce your risk is provide a thorough medical history before treatment, including any diagnosed conditions, medications (especially blood thinners), and any unusual symptoms like dizziness, visual changes, or numbness. If a chiropractor doesn’t ask about these things or skips a physical examination before your first adjustment, that’s a reason to find a different provider.