A variety of analgesic strategies are available following mixed hemorrhoids surgery, including pharmacological interventions (7), acupuncture, moxibustion, and electroacupuncture . Medications such as opioid analgesics and non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used but can be associated with side effects including nausea, vomiting, and gastrointestinal bleeding, with long-term use potentially leading to addiction (8). Complementary therapies require skilled administration and regular treatment sessions.

Methylene blue (MB), a cationic thiazine dye extensively utilized as a biological stain and chemical indicator, has been increasingly recognized for its potential analgesic properties (9). In the present study, methylene blue infiltrating injection (MBI) was administered to treat anal pain resulting from Milligan-Morgan surgery, with the aim of assessing its analgesic efficacy and safety profile.

Inclusion Criteria:①Alignment with the diagnostic criteria for mixed hemorrhoids as outlined in the "American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Hemorrhoids" ; ②Provision of informed consent following a thorough comprehension of the study's aims; ③An age bracket of 18 to 75 years; ④Satisfaction of surgical indications.

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Exclusion Criteria:①Presence of anal fistula, anal fissure, perianal abscess, enteritis, or other intestinal pathologies; ②Patients with known allergies; ③Impaired liver or kidney function; ④Pregnancy or lactation.

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