diff --git a/src/stable.rs b/src/stable.rs
index abfeab3..ad9870c 100644
--- a/src/stable.rs
+++ b/src/stable.rs
@@ -403,6 +403,8 @@
 
 impl Term {
     pub fn new(string: &str, span: Span) -> Term {
+        validate_term(string);
+
         Term {
             intern: SYMBOLS.with(|s| s.borrow_mut().intern(string)),
             span: span,
@@ -426,6 +428,42 @@
     }
 }
 
+fn validate_term(string: &str) {
+    let validate = if string.starts_with('\'') {
+        &string[1..]
+    } else if string.starts_with("r#") {
+        &string[2..]
+    } else {
+        string
+    };
+
+    if validate.is_empty() {
+        panic!("Term is not allowed to be empty; use Option<Term>");
+    }
+
+    if validate.bytes().all(|digit| digit >= b'0' && digit <= b'9') {
+        panic!("Term cannot be a number; use Literal instead");
+    }
+
+    fn xid_ok(string: &str) -> bool {
+        let mut chars = string.chars();
+        let first = chars.next().unwrap();
+        if !(UnicodeXID::is_xid_start(first) || first == '_') {
+            return false;
+        }
+        for ch in chars {
+            if !UnicodeXID::is_xid_continue(ch) {
+                return false;
+            }
+        }
+        true
+    }
+
+    if !xid_ok(validate) {
+        panic!("{:?} is not a valid Term", string);
+    }
+}
+
 impl fmt::Debug for Term {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_tuple("Term").field(&self.as_str()).finish()