It made headlines 25 years ago when it killed dozens of American women and caused serious illness for thousands of others.

Now, there are signs that toxic shock syndrome (search) may be making a comeback.

"There probably was a period in the late 1980s that it pretty well disappeared, and I have a feeling that it's coming back," said Dr. James Cherry of UCLA Medical Center (search).

Toxic shock syndrome is a bacterial infection, commonly associated with tampon use in women, that causes flu like symptoms, as well as more sever symptoms like hair loss. If left untreated, it can be fatal.

According to the FDA, the number of cases of TSS declined significantly throughout the 1990s, with only two cases reported in 1998. The National Center for Health Statistics (search) was so convinced that TSS was no longer a public health threat that it stopped collecting data on the condition. However, incidents are suddenly up nationwide. California has seen a spike in cases from just 10 in 2003 to 41 in 2004—a 400 percent increase.

"It's still around, there's no doubt about it, and it's a serious disease when somebody gets it," said Dr. James Todd of Children's Hospital of Denver.

Doctors are concerned not only with the rise in cases, but with the public's decreased immunity to the infection since TSS peaked 20 years ago. They say a new strain of the bacteria is emerging, and that they may actually be less equipped to fight TSS today than they were two decades ago.

Health experts say there are other problems. Though doctors warn against wearing a tampon overnight, literature from many manufacturers, as well as the FDA, say that overnight use is safe. They also fear that young women between the ages of 12-15 — who are most at risk for contracting the infection— may never have heard of toxic shock syndrome and may be unprepared to guard against it.

Click on the video box at the top of this story to see a report by FOX News' Anita Vogel.