Just remember that when you spray the stuff on your clothes that you're not wearing them. Permethrin is a neurotoxin and can cause severe problems if it contacts the skin in sufficient amounts:
- Irritation of skin and eyes.
- Irritability to sound or touch, abnormal facial sensation, sensation of prickling, tingling or creeping on skin, numbness.
- Headache, dizziness, nausea, vomiting, diarrhea, excessive salivation, fatigue.
- In severe cases: fluid in the lungs and muscle twitching may develop. Seizures may occur and are more common with more toxic cyano-pyrethroids.

If you have cats, keep it away from them--it will kill them.

Spray it on your clothes outside and let them dry. Once dry, Permethrin is inert but it will still kill the ticks, mosquitos, etc. Permethrin will also last through one or two clothes washing cycles before you have to re-apply it.