With a view to ensuring the proper and effective enforcement of Legislative Decree No. 336 of 4 August 1999, the Minister of Health has adopted the present Circular. The Circular lays down the guidelines to be followed to interpret and apply the said Legislative Decree. Particular regard is given to the following issues: National Plan for the Detection of Residues; controls to be carried out by operators; penalties; monitoring on feedingstuffs, farms and slaughterhouses. Five Annexes containing