Progesterone capsules are a prescription medication with an adverse reaction item in its instructions suggesting breakthrough bleeding, spotting vaginal bleeding, weight gain or loss, cervical squamocolumnar junction changes, changes in the nature of cervical discharge, breast swelling, nausea, dizziness. Headache, lethargy, fever, insomnia, allergy with or without itching, melasma, melasma, obstructive xanthogranuloma, abnormal liver function. The results of a study conducted in the literature on the effectiveness of treatment with estrogen and progesterone preparations in women with low estrogen levels showed that among 56 women treated with progesterone capsules, 3 women experienced symptoms of breast distention and 1 woman experienced symptoms of menstrual disorders, and the incidence of adverse reactions was 7.14%. In the clinical observation of progesterone treatment for pre-eclampsia due to luteal insufficiency, some literature showed that the total effective rate was 94.44% in 36 patients with pre-eclampsia, including 2 cases of gastrointestinal discomfort, 1 case of breast distension and 1 case of dizziness, and the incidence of adverse reactions was 11.1%. Some literature studies have shown that the clinical efficacy of progesterone capsules in the treatment of luteal insufficiency causing pre-eclampsia is better than that of intramuscular injection administration, with a lower incidence of adverse reactions and better clinical compliance. In summary, the side effects of progesterone capsules include breakthrough bleeding, spotting vaginal bleeding, weight gain or loss, cervical squamocolumnar junction changes, changes in the nature of cervical discharge, breast swelling, nausea, dizziness. headache, feeling of lethargy, fever, insomnia, allergy with or without scratching, melasma, chloasma, obstructive xanthogranuloma, abnormal liver function. Patients should take the drug as prescribed by their doctor. Inform the doctor promptly if new side effects are discovered during the course of medication use.