Sodium 4-aminosalicylate dihydrate (4-Amino-salicylic acid sodium salt) is the sodium salt form of aminosalicylic acid, an analog of para-aminobenzoic acid (PABA) with antitubercular activity. Sodium 4-aminosalicylate dihydrate exerts its bacteriostatic activity against Mycobacterium tuberculosis by competing with PABA for enzymes involved in folate synthesis, thereby suppressing growth and reproduction of M. tuberculosis, eventually leading to cell death.