About tetracyclinea broad-spectrum polyketide antibiotic,tetracycline derivative.mechanism of action of tetracyclinetetracycline is a broad spectrum antibiotic which has more specific action against gram positive organisms than gram negative organisms. it exerts its bacteriostatic action by accumulating inside the bacteria through specific transporter protein & inhibits bacterial protein synthesis by attaching to 30 s subunit of bacterial ribosome (which are absent in mammals). it chelates cations like ca &mg and inhibits functioning of various enzymes & ribosome. it is used in some areas for the treatment of chloroquine-resistant falciparum malaria