This open-label, multiple dose, single sequence crossover study will evaluate the drug-drug interaction between danoprevir/low-dose ritonavir and raltegravir in healthy volunteers. Subjects will receive raltegravir on Days 1-4 and, after a washout period of 3 days, danoprevir and low-dose ritonavir on Days 8-21, in combination with raltegravir on Days 18-21.

Inclusion Criteria:

• Healthy non-smoking male and female adults, 18 - 55 years of age, inclusive
• Healthy status defined by absence of evidence of any active or chronic disease
• Medical history without major, recent, or ongoing pathology
• Weight >/= 50.0 kg
• Body mass index (BMI) 18.0 - 32-0 kg/m2
• Willingness to abstain from alcohol, xanthine-containing beverages or food (e.g. coffee, tea, cola, chocolate, "energy drinks") from 48 hours prior to entry in the clinical site until discharge
• Females of child-bearing potential and males and their female partners of child-bearing potential must agree to use 2 forms of contraception, one of which must be a barrier method, during the study and for 90 days after the last drug administration. Acceptable barrier forms of contraception are condom and diaphragm; acceptable non-barrier forms of contraception for this study are non-hormonal intrauterine device (IUD) and/or spermicide

Exclusion Criteria:

• Pregnant or lactating females or males with female partners who are pregnant or lactating
• Any history of clinically significant cardiovascular or cerebrovascular disease, hypertension, and/or infections
• Positive test for drugs of abuse at screening or prior to admission to the clinical site during any study period
• Positive for hepatitis B, hepatitis C or HIV infection
• Current smokers or subjects who have discontinued smoking less than 6 months prior to first dose of study medication
• Use of hormonal contraceptives within 30 days before the first dose of study medication
• History of clinically significant drug-related allergy (such as anaphylaxis) or hepatotoxicity