• Coughing or wheezing, increased asthma, runny or stuffy nose

• Flu like symptoms, nausea, intestinal upset

• Dizziness, headaches, loss of balance

• Muscle twitches or painful skin spots

• Painful spasm of the hand, foot, or body

• Numbness, burning of the eyes, skin or throat

• Menstrual irregularities

• Miscarriage

• Feeling abnormally tired

• Increased salivation (check for this in pets too)

• Foggy memory or impaired concentration

Pyrethrins and pyrethroids interfere with the normal way that the nerves and brain function. Exposure to very high levels of these compounds for a short period in air, food, or water may cause dizziness, headache, nausea, muscle twitching, reduced energy, changes in awareness, convulsions and loss of consciousness. Changes in mental state may last several days after exposure to high levels of pyrethroids has ended. There is no evidence that pyrethrins or pyrethroids affect the ability of humans to produce children, but some animal studies have shown reduced fertility in males and females.

In air, all six of the pyrethrins and many of the pyrethroids are broken down rapidly (1-2 days) by sunlight or other compounds found in the atmosphere.

Pyrethrins and pyrethroids interfere with the way that the nerves and brain function. If you get a large amount of pyrethrins or pyrethroids on your skin, you may get feelings of numbness, itching, burning, stinging, tingling, or warmth that could last for a few hours. You are not likely to be exposed to amounts of pyrethrins or pyrethroids by breathing air, eating food, or touching anything that would cause enough pyrethrins or pyrethroids to enter your body and cause other problems. But if very large amounts of these chemicals were to enter your body, you might experience dizziness, headache, and nausea that might last for several hours. Larger amounts might cause muscle twitching, reduced energy, and changes in awareness. Even larger amounts could cause convulsions and loss of consciousness that could last for several days. Allergic reactions have been seen in a few individuals who used products that contain pyrethrins or pyrethroids. There is no evidence that pyrethrins or pyrethroids cause birth defects in humans or affect the ability of humans to produce children. There is evidence from animal studies that pyrethrins and pyrethroids might be capable of causing cancer in people, but the evidence comes from animals that ate very large amounts of pyrethrins or pyrethroids for a lifetime.

To protect the public from the harmful effects of toxic chemicals and to find ways to treat people who have been harmed, scientists use many tests.

One way to see if a chemical will hurt people is to learn how the chemical is absorbed, used, and released by the body; for some chemicals, animal testing may be necessary. Animal testing may also be used to identify health effects such as cancer or birth defects. Without laboratory animals, scientists would lose a basic method to get information needed to make wise decisions to protect public health. Scientists have the responsibility to treat research animals with care and compassion. Laws today protect the welfare of research animals, and scientists must comply with strict animal care guidelines.

Animal studies show effects of pyrethrins and pyrethroids similar to those seen in people exposed to very high amounts of these chemicals. In addition, exposure to pyrethrins or pyrethroids might affect the ability of some animals to reproduce and may also cause cancer.