Physician consultations---requests for skills and expertise from physicians of other specialties---are a critical yet underexamined component of inpatient care delivery. Despite the high prevalence of consults, their effects on health and utilization outcomes are uncertain. In this dissertation I provide descriptive evidence on the use of physician consults nationally and employ quasi-experimental methods to estimate the causal effects of consults. Chapter 1 explores trends in attending physician specialty and the use of consults among Medicare fee-for-service beneficiaries admitted to hospitals between 2010 to 2020. Leveraging claims data on over 11 million admissions, I find that generalist physicians, predominantly hospitalists, are the most common attending physician specialty. The share of admissions treated by generalist physicians increased from 54% in 2010 to 60% in 2020. Despite this shift, the use of consults remained relatively stable, with two-thirds of admissions involving at least one consult. In Chapter 2 I provide causal estimates of the effects of infectious disease and cardiology consults occurring in the first 24 hours of admission to general medicine. This analysis relies on detailed electronic health record data from a large health system spanning 2017 to 2024. To address the endogeneity of consults, I employ an instrumental variable approach: increases in consultant workload lead to decreases in the probability of a consult. Using 2SLS, I find that an infectious disease consult leads to a 70% reduction in the probability of being readmitted within 30 days of discharge, albeit with the tradeoff of a longer hospital stay and higher charges. Likely mechanisms include increases in the use of intravenous antibiotics and improved care continuity in the outpatient setting post-discharge. In contrast, cardiology consults appear to reduce hospital length of stay and costs over a 30-day episode. I find suggestive evidence that cardiology consults are used to “rule out” serious cardiovascular conditions among high-risk patients, facilitating earlier discharges. In summary, I show that consults are valuable in my setting and can substantially affect the care that patients receive, both in and out of the hospital.