(QMI Agency files)

A six-year-old British boy and his family are on high alert this season — the boy has an allergy to pine trees so severe that a Christmas tree could kill him.

Theo Lester of Norfolk inherited his extreme allergy from his mother, and risks going into anaphylactic shock if he even goes near a Christmas tree, U.K. newspaper the Sun reported Monday.

"Before he goes round to a friend's house, I have to make sure they only have a fake tree," Theo's mother Bree, 37, told the newspaper.

Bree's parents have a real Christmas tree, so when she and Theo go to visit they have to stay in a different room.

Theo would prefer a real Christmas tree himself except for the fact that "they make (him) feel poorly."

The boy has other allergies that make mince pies and Christmas pudding out of bounds, too.