The study was stopped for ethical reasons to give the placebo group the same treatment.

After eight weeks, there was no difference between the placebo group and those who took the herb.

For those in the placebo group, the operation stopped there.

Those in the placebo group received a drug that put them to sleep.

Without a placebo group to compare against, it is not possible to know whether the treatment itself had any effect.

Nearly all studies conducted find benefit in the placebo group.

However, men in the placebo group saw a 2.99 point drop.

By contrast, a placebo group lost only about three pounds.

These figures compared with 20 of 56, or 36 percent, in the placebo group.

This was about double the 7 percent rate in the placebo group.