Antibiotic tablets (oral antibiotics) are usually used in combination with a topical treatment to treat more severe acne.
In most cases, a class of antibiotics called tetracyclines is prescribed, unless you're pregnant or breastfeeding.
Pregnant or breastfeeding women are usually advised to take an antibiotic called erythromycin, which is known to be safer to use.
It usually takes about 6 weeks before you notice an improvement in your acne.
Depending on how well you react to the treatment, a course of oral antibiotics can last 4 to 6 months.
Tetracyclines can make your skin sensitive to sunlight and UV light, and can also make the oral contraceptive pill less effective during the first few weeks of treatment.
You'll need to use an alternative method of contraception, such as condoms, during this time.