antihistamine. a drug that counteracts the effects of histamine, a normal body chemical that among its actions is believed to cause the symptoms of persons who are hypersensitive to various allergens.hile the term antihistamine can broadly include any agent that blocks any histamine receptor, in practice it is usually used to denote those blocking the H 1 type of receptors (H1 receptor antagonists), those involved in allergic reactions.
The Executive Branch. From the President, to the Vice President, to the Cabinet, learn more about the Executive Branch of the government of the United States. The power of the Executive Branch is vested in the President of the United States, who also acts as head of state and Commander-in-Chief of the armed forces. The President is responsible for implementing and enforcing the laws written by Congress and, to that end, appoints the heads of the federal agencies, including the Cabinet.
The executive branch of our Government is in charge of making sure that the laws of the United States are obeyed. 1  The President of the United States is the head of the executive branch. The President gets help from the Vice President, department heads (called Cabinet members), and heads of independent agencies. Here are some of the things those people do: 1  The President leads the country and commands the military. 2  The Vice President becomes President if the President can no longer do the job and is also President of the Senate. 3  Department heads advise the President on issues and help carry out decisions made by the Government.