What is the best over-the-counter medicine for allergies?

It depends. You have to be cautious with any medication. Some antihistamines may cause you to be drowsy and impair you specially when driving, others do not have this effect. Read labels carefully and determine what is best for your lifestyle. Avoidance of triggering factors is useful if you know what you are allergic to. A visit to the allergist may be in order!
No BEST. There is actually no best otc allergy medicine. You just have to try the different ones out there and see what works well for you. I highly recommend using saline nasal wash or rinse regularly. If nothing seems to work, then see your doctor for prescription medications for allergies.
Cetirizine/Zyrtec. Assuming that "allergies" means itchy eyes, sneezing, nasal congestion, runny nose, post-nasal drip caused by contact with inhaled substances to which you are allergic (e.g. Pollen, pets, dust, mold), then Cetirizine (generic of zyrtec) 10 mg, 1 tab, at bedtime is most likely to give you relief. Cetirizine can cause sedation; most peopel who take it at bedtime are fine next am.

Related Questions

What's the best over-the-counter medicine for spring allergies? I'm an 18 year old female

Several choices. There are several. Zyrtec, allegra, or Claritin (loratadine) to name three.All work well, with minimal side effects. Read more...
CLARITIN/ZYRTEC/ALLE. Of the non sedating ones zyrtec/claritin/allegra are all good for an 18 years old all available over the counter in brand name and generic version as well. Read more...
Depends. I am fond of fexofenadine (Allegra) as what works best for me and is non-sedating. Loritadine (Claritin) is relatively cheep, non sedating and works well for many. Zyrtec (citerazine) is somewhat sedating so I seldom recommend it. If you will accept a nose spray, many of the OTC nasal steroids (like Rhinocort) are helpful and help reduce the swelling inside your nose. Read more...

What is the best over-the-counter allergy medicine for seasonal allergies? I heard OTC nose sprays should be avoided?

Allergy. Otc decongestant nose sprays like afrin are very helpful but can only be used 3-4 days. Medications like zyrtec and Allegra are very good. Nasal saline spray is good because it washes out pollen, etc from nose and also acts as mild decongestant. Eye drops like visine allergy are very helpful. Nasal crom nasal spraay is helpful and safe but inconvienent because it requires frequent use. Read more...

What is the best over-the-counter allergy medicine to use?

Allergy medications. Unfortunately there is no "best" brand. Different patients respond better to one medication than to another. Loratadine, diphenhydramine, fexofenadine and certrizine are all effective. Read more...
Several. There are several OTC allergy medicines that can be used. Choosing the right one will depend upon the symptoms one is having. Read more...

What is the best over-the-counter allergy medicine for curing itchy eyes?

Saline/antihistamine. You can try any over the counter antihistamine eye drops, avoid any that have additional medications in them such as a vasoconstrictor because they can cause rebound effect. Some examples: zyrtec, claritin, zaditor (ketotifen). Also use saline throughout the day which will help. Keep drops cool in refrigerator to provide more relief. Read more...