The antibiotics most commonly used to treat diverticulitis include metronidazole, ciprofloxacin, ceftriaxone, and co-amoxiclav. However, the choice of antibiotic depends on the severity and type of diverticulitis, as well as the patient's medical history and any allergies.

Metronidazole is a common first-line antibiotic for uncomplicated diverticulitis. It is a good choice for people who have a higher risk of complications, such as those with diabetes or an underlying medical condition. It is also used for people who cannot take the other antibiotics due to allergies or other medical reasons. Metronidazole is generally safe for most people, but it can cause side effects such as nausea, vomiting, and headache.

Ciprofloxacin is another common antibiotic for diverticulitis. It is a good choice for people who have a higher risk of complications, such as those with diabetes or an underlying medical condition. It is also used for people who cannot take the other antibiotics due to allergies or other medical reasons. Ciprofloxacin can cause side effects such as diarrhea, nausea, and vomiting.

Ceftriaxone is an intravenous antibiotic that is sometimes used for severe cases of diverticulitis that require hospitalization. It is a broad-spectrum antibiotic that can treat a wide range of infections, including those caused by bacteria. It is generally safe for most people, but it can cause side effects such as nausea, vomiting, and diarrhea.

Co-amoxiclav is an oral antibiotic that is sometimes used for severe cases of diverticulitis that require hospitalization. It is a combination of amoxicillin and clavulanic acid, which works to fight off bacteria that have become resistant to other antibiotics. It is generally safe for most people, but it can cause side effects such as nausea, vomiting, and diarrhea.

It is important to note that the choice of antibiotic for diverticulitis should be made by a healthcare professional, such as a doctor or nurse practitioner, based on the individual's medical history, current condition, and severity of the infection. Additionally, it is important to take the antibiotics as prescribed, even if symptoms improve before the full course of treatment is complete.