This is a single center, single blind, single dose, randomized, partial cross-over study to confirm bioequivalence between levocetirizine and cetirizine.

Inclusion Criteria:

1. Japanese healthy male subjects aged between 20 and 64 years of age inclusive. Healthy subjects are defined as individuals who are free from clinically significant illness or disease as determined by their medical history, physical examination, laboratory studies, and other tests.

2. Body weight ≥ 50 kg and BMI within the range 18.50-25.00 kg/m2 inclusive.

3. Non-smokers (at least 6 months).

4. Clinical laboratory tests data obtained at screening meet the following:

   AST(GOT), ALT(GPT), total-bilirubin, BUN, creatinine, uric acid,: below the upper normal range

5. Normal 12-lead EGC finding at screening; QTc interval <450msec

6. Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form.

Exclusion Criteria:

1. The subject has any clinically relevant abnormality on medical examination, vital sign, clinical laboratory test or medical history at screening in the medical opinion of the investigator or the subject has a medical history that is not considered as eligible for inclusion in this study by the investigator.
2. The subject has an allergy for any drug or idiosyncrasy.
3. The subject has a history of allergic rhinitis.
4. The subject has a history or presence of clinically significant gastrointestinal, hepatic or renal disease or other condition known to interfere with absorption, distribution, metabolism or elimination of drugs.
5. The subject is currently participating in another clinical study or post-marketing study in which the subject is or will be exposed to an investigational or a non-investigational drug or device.
6. The subject has participated in a clinical study with an investigational or a non-investigational drug or device during the previous 4 months.
7. The subject has a history or current conditions of drug abuse or alcoholism.
8. History of regular alcohol consumption exceeding on average, 14 drinks/week (1 drink = 150mL of wine or 360mL of beer or 45mL of 80 proof distilled spirits).
9. The subject is positive for urine drug screening.
10. The subject is positive for syphilis, HBs antigen, HCV antibody, HIV antibody, HTLV-1 antibody.
11. The subject has donated a unit of blood ">400mL" within the previous 4 months or ">200mL" within the previous 1 month.