diff --git a/changelog.d/pr489.bugfix.rst b/changelog.d/pr489.bugfix.rst
new file mode 100644
index 00000000..0965c14c
--- /dev/null
+++ b/changelog.d/pr489.bugfix.rst
@@ -0,0 +1,3 @@
+``Version.next_version`` now validates used prerelease tokens and matches token
+families literally. Invalid tokens raise ``ValueError``. Dotted prefixes advance
+correctly while existing qualifier chains and legacy counters are preserved.
diff --git a/src/semver/version.py b/src/semver/version.py
index 67274467..7ead382e 100644
--- a/src/semver/version.py
+++ b/src/semver/version.py
@@ -542,16 +542,26 @@ def next_version(self, part: str, prerelease_token: str = "rc") -> "Version":
             return getattr(version, "bump_" + part)()
         else:
             if version.prerelease and prerelease_token:
+                prerelease_token = str(prerelease_token)
+                cls._validate_identifiers(
+                    prerelease_token,
+                    cls._PRERELEASE_IDENTIFIER,
+                    "prerelease token",
+                )
                 # Handle old-style prereleases like "rc3" (no dot separator)
-                match = re.match(f"^{prerelease_token}(\\d+)$", version.prerelease)
+                match = re.fullmatch(
+                    rf"{re.escape(prerelease_token)}(\d+)", version.prerelease
+                )
                 if match:
                     num = int(match.group(1))
                     return version.replace(
                         prerelease=f"{prerelease_token}{num + 1}", build=None
                     )
 
-                current_token = version.prerelease.split(".")[0]
-                if current_token != prerelease_token:
+                if not (
+                    version.prerelease == prerelease_token
+                    or version.prerelease.startswith(prerelease_token + ".")
+                ):
                     return version.replace(prerelease=f"{prerelease_token}.1", build=None)
             return version.bump_prerelease(prerelease_token, bump_when_empty=True)
 
diff --git a/tests/test_bump.py b/tests/test_bump.py
index fcbedf4c..767d38f4 100644
--- a/tests/test_bump.py
+++ b/tests/test_bump.py
@@ -1,6 +1,7 @@
 import pytest
 
 from semver import (
+    Version,
     bump_build,
     bump_major,
     bump_minor,
@@ -152,6 +153,52 @@ def test_should_ignore_build_on_prerelease_bump():
     assert bump_prerelease("3.4.5-rc.1+build.4") == "3.4.5-rc.2"
 
 
+@pytest.mark.parametrize(
+    "version,token,expected",
+    [
+        ("1.2.3-alpha.beta.1+build.7", "alpha.beta", "1.2.3-alpha.beta.2"),
+        ("1.2.3-alpha.beta.gamma.1", "alpha", "1.2.3-alpha.beta.gamma.2"),
+        ("1.2.3-rc3", "rc", "1.2.3-rc4"),
+        ("1.2.3-rc.3", "rc", "1.2.3-rc.4"),
+        ("1.2.3-alphaXbeta9", "alpha.beta", "1.2.3-alpha.beta.1"),
+    ],
+)
+def test_next_version_matches_literal_prerelease_token_family(
+    version, token, expected
+):
+    original = Version.parse(version)
+    result = original.next_version("prerelease", token)
+    assert str(result) == expected
+    assert Version.parse(str(result)).to_tuple() == result.to_tuple()
+    assert str(original) == version
+
+
+@pytest.mark.parametrize(
+    "token", ["[", "rc.", "rc+build", "rc..next", "rc.01", "01", "ré"]
+)
+def test_next_version_rejects_invalid_prerelease_token(token):
+    with pytest.raises(ValueError):
+        Version.parse("1.2.3-rc.1").next_version("prerelease", token)
+
+
+@pytest.mark.parametrize("token", [None, ""])
+def test_next_version_preserves_empty_token_semantics(token):
+    version = Version.parse("1.2.3-alpha.beta.1")
+    assert str(version.next_version("prerelease", token)) == "1.2.3-alpha.beta.2"
+
+
+@pytest.mark.parametrize(
+    "part,token,expected",
+    [
+        ("major", "rc.", "2.0.0"),
+        ("minor", "rc+build", "1.3.0"),
+        ("patch", "rc..next", "1.2.4"),
+    ],
+)
+def test_next_version_ignores_token_for_main_parts(part, token, expected):
+    assert str(Version.parse("1.2.3").next_version(part, token)) == expected
+
+
 @pytest.mark.parametrize(
     "version,expected",
     [
@@ -163,4 +210,4 @@ def test_should_ignore_build_on_prerelease_bump():
 )
 def test_should_bump_build(version, expected):
     assert bump_build(version) == expected
-    assert compare(version, expected) == 0
\ No newline at end of file
+    assert compare(version, expected) == 0