Pain in the lower right abdomen has a long list of possible causes, ranging from a pulled muscle to a surgical emergency like appendicitis. The most likely explanation depends on how the pain started, how severe it is, and whether you have other symptoms like fever, nausea, or changes in your bathroom habits. Here’s a breakdown of the most common and important causes.
Appendicitis
Appendicitis is the first thing most people (and most doctors) think of when pain shows up in the lower right abdomen. The appendix sits in this area, and when it becomes inflamed or infected, it produces a distinctive pain pattern. It typically starts as a vague ache around the belly button, then migrates over several hours to a specific spot about halfway between the belly button and the right hip bone. That spot, sometimes called McBurney’s point, is where pressing with one finger usually produces the sharpest tenderness.
Other hallmarks include nausea, vomiting, loss of appetite, low-grade fever, and pain that worsens with coughing, walking, or sudden movements. Not everyone follows the textbook pattern, though. In some people the pain stays diffuse, and in pregnant women or older adults it can appear in unusual locations.
If appendicitis is suspected, a CT scan is the gold standard for confirmation, with a sensitivity around 97% and specificity near 96%. Ultrasound is often used first in children and pregnant women, though its accuracy is lower, catching roughly 81 to 87% of cases. Surgery to remove the appendix remains the standard treatment. For uncomplicated cases without a burst appendix, antibiotics alone can work, but the treatment success rate is about 18% lower than surgery, and roughly 1 in 5 people treated with antibiotics alone will have appendicitis come back.
Kidney Stones
A stone moving through the right kidney or ureter can produce intense pain that starts in the flank (the side of your back, below the ribs) and radiates downward into the lower abdomen and groin. This pain tends to come in waves, building to a peak and then easing before returning. It’s often described as one of the most severe pains a person can experience.
Along with the pain, kidney stones commonly cause bloody or cloudy urine, pain during urination, a persistent urge to urinate, nausea, vomiting, and sometimes fever or chills. The key distinction from appendicitis is the radiation pattern: kidney stone pain moves from back to front and often reaches into the groin, while appendicitis pain tends to settle in one spot in the lower abdomen and stay there.
Inguinal Hernia
An inguinal hernia occurs when tissue, usually part of the intestine, pushes through a weak spot in the lower abdominal wall near the groin. These hernias develop on the right side more often than the left and are far more common in men, though women can get them too. The classic sign is a visible or palpable bulge in the groin area, sometimes extending into the scrotum in men.
The pain from an inguinal hernia tends to feel like discomfort, heaviness, or a burning sensation in the groin. It gets worse when you strain, lift, cough, or stand for a long time, and it typically improves when you lie down. A hernia that can be gently pushed back into the abdomen is less urgent, but one that suddenly becomes painful, hard, and impossible to push back in is a medical emergency. This means the hernia is “strangulated,” cutting off blood flow to the trapped tissue. Warning signs include sudden severe pain, nausea, vomiting, fever, and redness over the hernia.
Crohn’s Disease
Crohn’s disease most commonly affects the end of the small intestine and the beginning of the large intestine, which sit in the lower right abdomen. This is why flare-ups often produce cramping and pain in exactly that spot, and why Crohn’s is sometimes initially mistaken for appendicitis.
The difference is the pattern over time. Crohn’s pain is chronic or recurrent, not a single acute episode. It usually comes alongside diarrhea (sometimes bloody), fatigue, weight loss, reduced appetite, mouth sores, and sometimes drainage or pain near the anus from fistulas. If you’ve had repeated bouts of lower right pain with diarrhea and weight loss, Crohn’s is worth investigating.
Mesenteric Lymphadenitis
Mesenteric lymphadenitis is swelling of the lymph nodes in the tissue that connects the intestines to the abdominal wall. It mainly affects children and teenagers and is most often triggered by a viral infection like stomach flu. The pain localizes to the lower right side, mimicking appendicitis closely enough that it’s one of the most common reasons kids end up with imaging or surgery for suspected appendicitis that turns out to be something else.
Clues that point toward lymphadenitis over appendicitis include recent or current symptoms of a viral illness (sore throat, runny nose, diarrhea), a more generalized abdominal tenderness rather than one sharp spot, and a less dramatic overall picture. Most cases resolve on their own without treatment.
Causes Specific to Women
Several gynecological conditions can cause pain that centers in the lower right abdomen. Ovarian cysts on the right ovary can produce a dull ache or sharp pain, especially if a cyst ruptures or twists. Ovulation pain, sometimes called mittelschmerz, causes a brief, sharp twinge on one side mid-cycle when an egg is released. Endometriosis, where tissue similar to the uterine lining grows outside the uterus, can cause chronic pelvic pain that may concentrate on the right side. Pelvic inflammatory disease, an infection of the reproductive organs usually linked to sexually transmitted bacteria, produces lower abdominal pain along with abnormal discharge, fever, and pain during intercourse.
An ectopic pregnancy, where a fertilized egg implants outside the uterus (most often in a fallopian tube), is a true emergency. It causes sharp, sudden pain on one side of the lower abdomen, often with vaginal bleeding, dizziness, or shoulder pain. Anyone with a positive pregnancy test and sudden one-sided abdominal pain needs immediate evaluation.
Causes Specific to Men
Testicular torsion, where the spermatic cord twists and cuts off blood supply to the testicle, can cause pain that radiates into the lower abdomen on the affected side. The primary symptom is sudden, severe testicular pain and swelling, but the abdominal pain can sometimes be the more prominent complaint, especially in younger boys. This is a time-sensitive emergency: the testicle can be permanently damaged within hours.
Inguinal hernias, covered above, are also much more common in men and remain one of the leading causes of lower right abdominal pain in this group.
Digestive Causes
Beyond the conditions already listed, several common digestive problems can produce lower right abdominal pain. Trapped gas or constipation can cause localized discomfort anywhere in the abdomen, including the lower right. Irritable bowel syndrome produces cramping, bloating, and changes in bowel habits that may favor one side. A bout of gastroenteritis (stomach flu) can cause diffuse or localized cramping throughout the abdomen.
Cecal diverticulitis, inflammation of a pouch in the cecum (the first part of the large intestine on the right side), is less common than left-sided diverticulitis but does occur, particularly in younger adults and people of Asian descent. It presents much like appendicitis and is often only distinguished through imaging.
Red Flags That Need Immediate Attention
Certain features of lower right abdominal pain signal a potential emergency. These include a rigid or distended abdomen, severe pain with guarding (where your muscles tense involuntarily when the area is touched), bilious (green) vomiting, signs of gastrointestinal bleeding such as vomiting blood or passing dark tarry stools, fainting or near-fainting, and high fever. Sudden severe pain in anyone who is pregnant, on blood thinners, or has a known abdominal aortic aneurysm also warrants immediate evaluation.
Pain that started gradually and is mild, without fever or vomiting, is less likely to be an emergency but still worth getting checked if it persists for more than a day or two, keeps coming back, or progressively worsens.