In recent years, the incidence of ectopic pregnancy has been increasing. Patients with ectopic pregnancy who have undergone tubal rupture should be promptly treated surgically, but their fallopian tubes are mostly difficult to be preserved. Pharmacological treatment is mainly indicated for young patients with early tubal pregnancy who require preservation of fertility. Pharmacological treatment can be considered if the following conditions are met: 1) no contraindications to pharmacological treatment; 2) no rupture of the tubal pregnancy; 3) gestational sac diameter ≤ 4 cm; 4) blood hCG < 2000 IU/L; 5) no significant internal bleeding. Methotrexate is a cell cycle specific drug that can prevent the synthesis of purines and pyrimidines, interfere with the synthesis of DNA and cell multiplication, thus inhibiting the growth and reproduction of trophoblast cells, and has become the drug of choice for the treatment of ectopic pregnancy because it has the advantages of low damage to the ovaries, convenient administration and low cost. This drug is mainly used for young women with stable vital signs, normal liver function, red blood cells, white blood cells and platelets and with fertility requirements, especially if the contralateral fallopian tube has been removed or has obvious lesions. Single dose treatment: Intramuscular injection of MTX based on 50 mg/m2 body surface area. single intramuscular injection regimen has become the standard of conservative treatment for tubal pregnancy at home and abroad for its efficacy and minimal side effects. side effects: (1) drug side effects include nausea, vomiting, stomatitis, diarrhea, stomach pain and dizziness, elevated liver transaminases, etc.; (2) treatment side effects include increased abdominal pain ( (2) Treatment side effects include increased abdominal pain (occurring in 2/3 of patients), usually found 2-3 days after injection, possibly due to separation of the product from the implantation site, which differs from tubal rupture in that it is moderate and limited (lasting 24-48 hours) and is not associated with acute abdominal pain or signs of hemodynamic instability. In clinical practice over the years, it has been found that many patients have to be re-dosed due to unsatisfactory hCG descent. There are no studies on repeat dosing of MTX. However, it has been suggested that repeat dosing may be related to MTX dose and blood hCG levels. However, if abdominal pain worsens during conservative treatment, it may be a ruptured lesion with increased intra-abdominal bleeding, which requires the option of emergency surgical treatment!