Lithium aluminum hydride reduces carboxylic acids to alcohols.

acidos-carboxilicos-reduccion
 
A possible mechanism for this reduction is the following:
 
Step 1. Deprotonation of the carboxylic acid
 
acidos-carboxilicos-reduccion
 
Stage 2. Nucleophilic attack of the hydride
 
acidos-carboxilicos-reduccion
 
Stage 3. Displacement of oxygen with the hydride ion
 
acidos-carboxilicos-reduccion
 
Stage 4. Hydrolysis
 
acidos-carboxilicos-reduccion