This randomized, open-label, multiple-dose, 2-period crossover study will evaluate potential drug-drug interactions between darunavir and danoprevir when administered together with low-dose ritonavir in healthy volunteers. In Period 1, subjects will be randomized to receive either darunavir or danoprevir together with low-dose ritonavir for 10 days. In Period 2, all subjects will receive darunavir plus danoprevir together with ritonavir for 10 days. Anticipated time on study treatment is 20 days.

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 >/= 55 kg
• Body mass index (BMI) 18.0 - 32.0 kg/m2
• Ability and willingness to abstain from alcohol, xanthine-containing beverages or food (coffee, tea, cola, chocolate, "energy drinks") from 72 hours prior to entry in the clinical site center 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