1. Police Pollen: Click on the National Allergy Bureau's website for a daily ranking of allergens, including seasonal tree pollens, grasses, weeds, and outdoor molds. Stay indoors when levels are high or very high for those that you're sensitive to.

2. Wear a mask: If you must finish that gardening before the in-laws show up, don a not-so-chic but très useful N95 filter mask, which keeps pollen out of your nose and mouth.   

3. Wash your hair at night: Rinse the pollen out, especially if you're a gel or mousse fan. These products can trap pollen.   

4. Soak up the calm: In one study, seasonal allergy (hay fever) sufferers had a more extreme reaction the day after performing a stressful task, such as giving a speech. "Stress raises levels of the hormone cortisol," says Clifford Bassett, MD, an allergist at New York University Medical Center, and that often leads to an amped-up allergic response. A few minutes of meditation or a soak in the tub should help.

5. Keep your nose clean: "Your nose is like a car windshield-pollen sticks to it," says Neil Kao, MD, an allergist at the Allergic Disease and Asthma Center, in Greenville, S.C. Try a saline sinus rinse, found at any drugstore. If that doesn't do it, buy the nonprescription herbal nasal spray NasalCrom (cromolyn sodium), which helps prevent allergic reactions in your nose.   

6. Take an antihistamine: There have never been more over-the-counter antihistamine options. You may be able to find relief with 10 milligrams of cetirizine (Zyrtec) once a day. If those don't work, ask your doctor for a prescription antihistamine such as fexofanadine (Allegra, but also available as a generic) or levocetirizine dihydrochloride (Xyzal).   

7. Try the sprays: If nasal washes and antihistamines don't work for you, up the ante with a prescription steroid spray like Flonase, but you can skip decongestants; Dr. Kao says they don't work for allergies and may worsen your congestion after several days of use.

8. Dust mites: Dust mites thrive in homes that are warmer than 70 degrees and have a humidity above 50 percent. Here's how to beat them. Cool (and dry) it Keeping your home temp in the mid to low 60s and the humidity between 40% and 45% should send them packing. Buy a home hygrometer to measure humidity levels.

9. Use barriers: To fight dust mites, look for mattress and pillow encasements at stores like Target, as well as online retailers like AllergyBuyersClub.com; costs range from $50 to $150 for bedding made from organic cotton.

10. Boil your bedding: Not literally, but you should wash your sheets and pillowcases weekly in water that's at least 140 degrees; a study in the Annals of Allergy, Asthma and Immunology found that this temperature wiped out all dust mites.

11. Outsource housekeeping: This won't take much arm-twisting, will it? Vacuuming and sweeping stir up dust mites and their droppings, which can take more than two hours to settle. If you can't hire someone else to clean your house while you're away, invest in a vacuum cleaner with a high-efficiency particulate air (HEPA) filter, like the Eureka Boss SmartVac)-and wear a trusty filter mask.    

12. Try acupuncture: At least one study and lots of anecdotal evidence suggest it can help. "I've seen amazing results in my allergic patients," says Roberta Lee, MD, vice chair of the Department of Integrative Medicine at the Beth Israel Medical Center, in New York City. She thinks acupuncture may decrease stress hormones, which can reduce inflammation. A session usually costs $100 to $150; ask your insurance company if some or all of that is covered.  

13. Indoor mold: Mold thrives in warmer, more humid weather. Don't assume it's not there just because you can't see it: Mold can hide under carpets, in walls, or anywhere. Here's how to beat it. Bleach it A 5% bleach solution and a rag or sponge can zap small mold problems. If you've got a very large moldy area (more than 10 square feet), consider hiring a mold-cleanup crew.   

14. Dry up rooms: Put an exhaust fan in bathrooms and laundry rooms, and a dehumidifier in unfinished basements.

15. Get HEPA: Filters, that is. Ideally, you want a central air-conditioning system with a HEPA filter attached. If you don't have central air, try free-standing air cleaners in key rooms such as the bedroom. Change the filters at least every three months and have your heating and air-conditioning units inspected (and cleaned, if necessary) every six.

16. Pet dander: If you're set off by pets, you may be allergic to proteins found in the animal's saliva, dander (dead skin flakes), and urine. And all furry pets carry these proteins; studies suggest hypoallergenic cats and dogs can cause just as many symptoms as the regular kind. Here are better steps you can take if you can't bear to part with Rover or Frisky. Ban him from the bedroom. Just keeping pets out (or better yet, away from your upstairs entirely) can help relieve your symptoms.   

17. Cut the rug: Consider replacing wall-to-wall carpeting with hardwood floors, tile, or linoleum, which won't trap dander.

18. Get him groomed: Your pet that is. Ask your nonallergic partner or child to comb him every day, preferably outside, with a comb dipped in distilled water, which traps dander. And a weekly bath (more often will dry his skin, making the dander problem worse) is a must.

19. Get shot: Immunotherapy has about an 85% effectiveness rate in decreasing allergic symptoms, including those triggered by animal proteins. You get one to two weekly shots to expose you to very small doses of the allergen, and the dose is gradually increased over about six months. You'll need maintenance shots about once a month for three to five years.