The invention provides an oral blocking agent for effectively inhibiting excessive absorbing of food starch. The oral blocking agent is prepared from the following raw materials of a sweetener, maltose powder, an acidity regulator, an anti-caking agent, white kidney bean extract, water-soluble fiber, tangerine fiber, kakorot extract, sodium bicarbonate, passion fruit essence, L-arabinose, essencepowder of lyme, a water retention agent, cactus extract, camellia japonica flower extract, roselle flower extract, radix gymnemae sylvestre extract, and chestnut skin extract. Compared with the priorart, the oral blocking agent has the beneficial effects that a buccal tablet product containing the natural enzyme blocking agent can be used for inhibiting the starch from being digested and absorbedby a human body, and the starch cannot be converted in the digestion process, so that the absorbing by the human body can be decreased; the inhibiting pancreatic lipase can be used for blocking the oil component from being decomposed into small molecules, and the small molecules are matched by the fiber, and then are carried out of the human body.