Though the Thanksgiving turkey has hardly had time to grow cold yet, it isn't too soon to start thinking about Christmas - and about how to have a safe yule.

Why the rush?Because the biggest shopping day of the year is usually the day after Thanksgiving. Because toys are always a big item with Christmas shoppers, with the $13 billion-a-year industry often prospering even when the rest of the economy is sour. (Parents, to their credit, will give up a lot of things rather than disappoint their children at Christmas.) And because toys still can bring death and injury as well as joy.

What a sad paradox. Even in the estimation of the ever-critical Consumer Products Safety Commission, the toy industry is doing a much better job of policing itself. Yet toy-related injuries continue to rise - from 113,000 in 1986 to 148,000 last year.

Many of those injuries could have been avoided if parents had chosen the toys more carefully, heeded age recommendation labels or monitored the use and condition of the toys as children play with them.

Infants and very small children are most at risk, which usually involves choking on small toys or their parts. Though the Consumer Product Safety Commission is preparing new regulations to deal with the choking hazards posed by some toys, the tougher rules won't go into effect until next year.

Meanwhile, parents would be well advised to think big when it comes to buying toys for children under 3. Examine toys carefully for small parts. If there are older children in the home, try to see that their toys are kept from younger children. Even if a toy is labeled "not intended for children under 3," it should not be bought for older children who still put small objects in their mouths. The experts also advise keeping uninflated or torn balloons from children under the age of 6.

One other pertinent point involves the recall of dangerous toys. Last year the government recalled 198 toys for dangers ranging from choking hazards to excessive lead in paints and sharp edges or points. But don't count on such measures to protect your family. Parents seldom hear about the recalls. Besides, even though recalled toys may be removed from store shelves, those already sold usually remain in use.

The bottom line is that when it comes to guarding against the dangers that can come with some toys, there's still no substitute for parental alertness.