Hans Rausing has pleaded guilty to a charge of preventing the lawful and decent burial of his wife Eva's body.
Rausing, who is one of Britain's richest men, also admitted driving while unfit through drugs at Isleworth Crown Court, west London.
Police discovered mother-of-four Mrs Rausing's decomposed body after they arrested her husband, who is heir to the Tetra Pak fortune, in July.
A post-mortem found she had died two months earlier and had drugs in her system, including cocaine. Her body was discovered in a room of their luxury London home under a pile of clothing and bin bags which had been taped together.
The court heard that Rausing told police in a statement after his arrest: "I do not have a very coherent recollection of the events leading up to and since Eva's death. Safe to assure you that I have never wished her or done her any harm."
The 49-year-old has been on bail since his arrest, on the condition that he reside at a private hospital in London, and only leave the building accompanied by a member of staff.