diff --git a/src/beedep_tree.c b/src/beedep_tree.c
index 39b2417..a11b433 100644
--- a/src/beedep_tree.c
+++ b/src/beedep_tree.c
@@ -31,7 +31,7 @@
 #include "beedep_tree.h"
 
 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
-#define ABS(a) (((a) < 0) ? (-a) : (a))
+#define ABS(a) (((a) < 0) ? (-(a)) : (a))
 
 struct tree *tree_new(void)
 {
diff --git a/src/graph.h b/src/graph.h
index c8e3389..964b83d 100644
--- a/src/graph.h
+++ b/src/graph.h
@@ -37,7 +37,7 @@
 
 #define IS_FILE(a)       ((a)[0] == '/')
 #define IS_DIR(a)        (!strcmp((a)->type, DIR))
-#define IS_WHITESPACE(a) (a == ' ' || a == '\t' || a == '\n' || a == '\r')
+#define IS_WHITESPACE(a) ((a) == ' ' || (a) == '\t' || (a) == '\n' || (a) == '\r')
 #define IS_PKG(a)        (!strcmp((a)->type, PACKAGE))
 
 #include "hash.h"