Galactosamine is a hexosamine derived from galactose with the molecular formula C6H13NO5. A few amino sugars, including galactosamine, have been shown to kill tumors in the laboratory. It is unlikely to be used in cancer therapy, however. D-galactosamine is a hepatotoxic, or liver-damaging, agent. Researchers studying animal models of liver failure sometimes use D-galactosamine to induce liver damage. Galactosamine is also helpful for researchers studying agents that might protect the liver from damage.

Galactitol (dulcitol) is a sugar alcohol, the reduction product of galactose. Galactitol is known to be the major toxic metabolites of galactose. Deficiency of any one of three possible enzymes involved in the metabolism of galactose: galactokinase, transferase or epimerase results in galactosemia. Any single deficient enzyme can result in cataract through the accumulation of galactitol in the lens. Accumulation of galactose and galactitol within the lens cells leads to an increase in intracellular osmotic pressure and an influx of fluid in the lens. Kinoshita was the first to demonstrate the hyperosmotic effects of intracellular sorbitol or galactitol accumulation and to postulate that the resulting cellular swelling can lead to increased membrane permeability and a series of complex biochemical changes associated with sugar cataract formation. The excretion of abnormal quantities of galactitol in the urine of galactosemia patients is characteristic of this disorder. A patent claims galactitol as carrier for the therapeutic agent since galactitol enhances the chemical and physical stability of the drug and allows faster reconstitution of the formulation in water than mannitol.

Bombesin (BN), a neuropeptide that originally was purified from the skin of the European frog (Bombina bombina). It has many biological effects including hormone release, stimulation of pancreatic enzyme secretion, gallbladder contraction and bronchoconstriction. Bombesin is a highly specific marker of neuroendocrine differentiation and thus a valuable tumor marker. It activates three different G-protein-coupled receptors known as BBR1, -2, and -3.