A. First of all, make sure that what he's saying is truly a lie. Often, when a preschooler fabricates a tall tale, he's fantasizing, not lying.
When a child talks about his invisible friend and his make-believe world, for example, it's totally harmless. In fact, when my little patients bring these pals to my office for a checkup, I provide an extra chair for their companion and even do a brief pretend exam.
Also, when a child tells his friends about his family's recent vacation to Disney World -- one you know never took place -- it's just whimsical, wishful thinking. It's normal for a young kid to make such claims, and you should confront him by simply saying, "I know you wish this is what happened." That helps set him up to tell the truth in the future because he learns he can't get anything -- even an innocent tale -- past you.
However, if your child spills a cup of milk on the carpet and blames it on the cat, that's a downright lie. Like many kids, he's probably distorted the facts because he knows he's done something wrong and is afraid of being punished. Then you need to nip this habit in the bud and teach your child the importance of telling the truth. Here's how:
If you remove the consequences, kids will more likely come clean. You can say, "No matter what you did, I promise I won't get angry as long as you tell the truth."
Let him know why it's wrong to lie. Tell him that it hurts people or that it makes you sad when he says things that aren't true. Make him want to be truthful by teaching him empathy -- asking him how he would feel if you lied to him. When my children were growing up and I knew that they were lying to me, I'd explain that I was hurt because they didn't tell me the truth. Usually, they'd soon come back and reveal what really happened because they felt better about being honest.