diff --git a/src/libsodium/include/sodium/private/common.h b/src/libsodium/include/sodium/private/common.h
index ed026909..954d02cc 100644
--- a/src/libsodium/include/sodium/private/common.h
+++ b/src/libsodium/include/sodium/private/common.h
@@ -234,10 +234,13 @@ xor_buf(unsigned char *out, const unsigned char *in, size_t n)
 #endif
 
 #ifdef HAVE_LIBCTGRIND
-extern void ct_poison(const void *, size_t);
-# define POISON(X, L) ct_poison((X), (L))
+extern void ct_poison  (const void *, size_t);
+extern void ct_unpoison(const void *, size_t);
+# define POISON(X, L)   ct_poison((X), (L))
+# define UNPOISON(X, L) ct_unpoison((X), (L))
 #else
-# define POISON(X, L) (void) 0
+# define POISON(X, L)   (void) 0
+# define UNPOISON(X, L) (void) 0
 #endif
 
 #endif