Mediates the transport of melibiose and other galactosides by a symport mechanism (PubMed:9188803). Can use protons and lithium as coupling cations, but not Na(+) (PubMed:9188803). H(+)(in) + melibiose(in) = H(+)(out) + melibiose(out) By melibiose. Belongs to the sodium:galactoside symporter (TC 2.A.2) family.