diff --git a/crates/typst-eval/src/markup.rs b/crates/typst-eval/src/markup.rs
index 5beefa912..9118ded56 100644
--- a/crates/typst-eval/src/markup.rs
+++ b/crates/typst-eval/src/markup.rs
@@ -205,7 +205,9 @@ impl Eval for ast::Label<'_> {
     type Output = Value;
 
     fn eval(self, _: &mut Vm) -> SourceResult<Self::Output> {
-        Ok(Value::Label(Label::new(PicoStr::intern(self.get()))))
+        Ok(Value::Label(
+            Label::new(PicoStr::intern(self.get())).expect("unexpected empty label"),
+        ))
     }
 }
 
@@ -213,7 +215,8 @@ impl Eval for ast::Ref<'_> {
     type Output = Content;
 
     fn eval(self, vm: &mut Vm) -> SourceResult<Self::Output> {
-        let target = Label::new(PicoStr::intern(self.target()));
+        let target = Label::new(PicoStr::intern(self.target()))
+            .expect("unexpected empty reference");
         let mut elem = RefElem::new(target);
         if let Some(supplement) = self.supplement() {
             elem.push_supplement(Smart::Custom(Some(Supplement::Content(
diff --git a/crates/typst-library/src/foundations/label.rs b/crates/typst-library/src/foundations/label.rs
index 403d50758..b8a08ac8d 100644
--- a/crates/typst-library/src/foundations/label.rs
+++ b/crates/typst-library/src/foundations/label.rs
@@ -53,9 +53,11 @@ pub struct Label(PicoStr);
 impl Label {
     /// Creates a label from an interned string.
     /// Callers need to ensure the given string is not empty.
-    pub fn new(name: PicoStr) -> Self {
-        debug_assert!(name != PicoStr::EMPTY);
-        Self(name)
+    pub fn new(name: PicoStr) -> Option<Self> {
+        match name {
+            PicoStr::EMPTY => None,
+            _ => Some(Self(name)),
+        }
     }
 
     /// Resolves the label to a string.
diff --git a/crates/typst-library/src/model/bibliography.rs b/crates/typst-library/src/model/bibliography.rs
index c9b9a4c7c..ef8d6b1f8 100644
--- a/crates/typst-library/src/model/bibliography.rs
+++ b/crates/typst-library/src/model/bibliography.rs
@@ -318,7 +318,12 @@ impl Bibliography {
                     bail!("bibliography key must not be empty");
                 }
 
-                match map.entry(Label::new(PicoStr::intern(key))) {
+                let label = match Label::new(PicoStr::intern(key)) {
+                    Some(lbl) => lbl,
+                    None => bail!("unexpected error while creating a label"),
+                };
+
+                match map.entry(label) {
                     indexmap::map::Entry::Vacant(vacant) => {
                         vacant.insert(entry);
                     }